Geological Survey Memoirs Scotland

THE OIB-SHALES

THE LOTHIANS (cTHIRD EDITION}

H.~ STATIONERY OFFICE 19t7

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DEPARniEm' OF SCIEl\l!fiC AND !NOUSTRlAL RESEARCH

.Memoirs of the Geological Survey, Scotland

The

Oil-Shales of the Lothians {THIRD EOITIO\")

PART I THE GEOLOGY OF THE OIL-SHALE FIELDS

By R. G. CARRUTHERS Based on the 11ror\ of H. \t, CADLt uu J. ~. CR.A'\"T WJL.SOS"

PART II .:'I!ETHODS OF \\'ORKIXG TilE OIL-SHALES

By II'. CALD\\ ELL

PART Ill CHE:\1ISTRY AND TECHNOLOGY OF THE

OIL-SHALES By F.. \I. JlAILeY

PART IV HISTORY OF THE SCOTTISH OIL-SHALE

I:\DUSTRY By H. R J. CO\ACHER

EDINBURGH PRINTED UNDER THE AUTHORITY OF IllS ~fAJESTY'S

STATIONER\' OfFICE To be purcb~ fron.

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Booksel!or, from lhc OIRECTOR-GI::~J:;R.\1., OKI>'ASCK SURVEY. S0VTHAliP'T0'

1927

62-52~17 Pruc ss 6J .".'11

PREFACE TO FIRST EDITION

THE following Memoir on the Oil-Shale Industry of Scotland is divided into three parts, and treats of the subject both in its geo-logical and technological aspects. Part I. treats of the Geology of the Oil-Shale Fields of the Lothians, and is the joint work of llr. H. ll. Cadell and lli. ]. S. Grant Wilson. After the opening up of the oil-shale industry it became nece....

PREFACE TO THIRD EDITIOK

IN preparing the third edition of the Oil-Shales of the Lothians, it has not been found necessary to alter :\lr. Carruthers's chapter on the Geology of the Oil-Shale Fields, except by the incorporation of a limited amount of new information furnished by recent mining de-velopments, boring, and exploration. This part has been edited bv ~lr. M. Macgre~;or. T he account of the Chemi~try and Technology of the 01-Shales, which in the previous editions wa> contributed by the late Mr. D. R. Steuart, has been entirely rt'-written by Mr. E. M. Bailey, of &ottish Oils, Limited, and represents accurately the present state of our knowledge of both the theoretical and practical problems of the chemistry of Scottish oil-shales and the manufacturing processes used in the industry. lli. Caldwell has revised his chapter on the :\lethods of Working the Oil-Shales, but the alterations are not extensi\"e. A new chapter has been added by Mr. H. R. ]. Conacher, of Scottish Oils, Limited, gi\-ing an outline of the history of the Scotti 1. Carlopo .

VII. On the Pro,ing ul Oil-Shale Strata \'Ill. The \\'e" Cald

VI. ~lethods of Working VII. Timbering of Le-.13

VIII. Gases and \entilahon IX. Pumping "'ater

vi

X . Underground Haulage . XI. Inclined Shaft Wmdmg

XII. Conveyance of ShaJe on Surface

PART UI

I'AG& t228

2J6

237

240

LIST OF ILLUST RATIONS

FIGURES IN TEXT PAG.E

Ftc. .-Index Map of mam Shale-lield,showingboundariesof Six-inch Quarlersbeets . . . . . . . i.'C.

2,-Genero.l Vertical Section of the Car-boniferous SLrnta of t\lid and \Vest Lothian . . . .

, 3.-Scction from &'\ad's Mill across Cobbinshaw Hill .. 4.-Seetion from Ba.ad 's l\-lill to Limefield Honse .

5.-Section from Limefield Mains to :\Iurieston , 6.-Section of Brcich and Polheth Shale-fields . , 7.-Scction across Deans and Li~ston ShaJe.fields

4 19 27

35 3i 40 46 .. 8.-Section across :U.dCalder and ::\e"iarm Shale-fields . .

9 .--Seetion across the Calder and l!urieston Faults through Oak bank Oil Works . . . . . 46

,. ro.-Seetion acroa th~ northern pan of the Pumpberstoo Shale .. field . . . . . . 51

I 1.-stction ac.ro&:s the

viii

Ftc. 43.-Pian of LongwaU Face -14.- Seetion of the Fells Shale. . .

., ~5.-.\iethod of Spragging Shale . . . , 46.-Special.\iethod ol Working Oil-Shale in Steps. .. 47.-Seetion of Dunnet Shale, Oak bank Pit, Alid-Caldtr ., 48.-Longitudinal Section, showing ~lethod of Working the

Dunnet Shale, Mid-Calder . . . ., 49.- l!ethod of Working Ycrtieal S...lll5 of Sh.lle .. ;o.-Roof supported b\' Crown Tree . . .

jt.-Roof supported b} Vertical Prop . . . . .. ;o.-Roof supported by Steel Girder, supported by Vertical Props

53.-{a) Briek-o=lling; (b) Brickwork and Corders . . ., 54.- Fan osed in \'entllating Shale Mines .

~5---)b) Brattice Boards; (.-Ventilation of Stoop and Room \Vorlnngs

6t.~uddie Brae . 62. -Chain Pulley and Brake . 63.- '"o

\"I. Treating Plant for Crude Do!tillate . , !"4 VII. Oil Coolers JOi

\'1 II. F'dter Press ,, :roh 1~. Hydraulic Preo.es . . .. >

GEOLOGICAL SURVEY MAPS OF THE SHALE-FIELDS TlUl shale-fields of the lothtans be almost wholly within Sheet 32 of th~ Geologicalllap of Scotland, 1n tbe countles of Lin.l.it:bgow and Edinburgh . but !Delude afso small areas on the ea.L margin of Sheet 31, on the north margin of Sheet 24 (parts of Lanark, Edinburgh, and Peebles), and on the sont h margin of Sheet 40 (File).

A special geologtcal map of the maio shale-field forms Plate XU. of this Memoir, while the numbers and boundaries o{ the included Si"

2 THE GEOLOGY Of THE OIL-SHALE FIFLD,

that region. The results of that resurvey were embodied in a second edition of Sheet 32, issued in 1892.

In 1885, Mr. Cadell communicated a brief dc:;cription of the results of his re-examination of the shale-fields to lhe meeting of the British Association at Aberdeen in a paJX>r entitled ' Rec.:nt Ad-Yances in West Lothian Geology.' He mdkated the po'itum of the various oil-shales then known in the cour:;e of mining OPO71 "rnd 19()1). 2 Yol. 'iii., pp. 11~162 ,read 1900).

GEOLOGICAL POSITIOl< Of TilE OIL-SHALE MEASURES 3

The geological portion of the pre..ent edition is substantially a reprint of that of I9I2, but a number of necessary corrections and additions have been made to the text and to some of the horizontal and vertical sections. The small-scale geological map which accom-panied the pre,ious editions has been replaced by one of the main shale-field on a larger scale.

I. GEOLOGICAL POSITIOl< OF THE 0JL-SIIALF: MEASURES

The oil-shale measure:; on which the oil industry depends form pan of tbe Calciferous Sandstone Series of :Uid and West Lothian and the southern coast of Fife between Burntbland and Inverkeithing, the g~logical position of which will be readily grasped from the follo"'lllg tabular statement {sa also Fig. 2).

The Carboniferous System in Scotland may be arranged in descending order in four divisions as given below.

4 Coal Jf easures, comprising red sandstones, shales, and marls with no workable coals, underlaid by white and grey sandstones and shales with numerous ,aluable coal-seams and ironstones.

3 Jlillstrme Grit, consisting chiefly of thick, often coarse sand-~tones with beds of fireclay, a few thin coals. iron.tones, and thin lime stones.

2. Carbonifcr~Jus Lime stone Series, embracing three subdivisions, the highest of which contains three or more limestones with thick beds of sandstone and some coals : th!' middle includes valuable seams of coal and ironstone ; and the lowest is characterised by several beds of marine limeotone, with sandstone, shales, some coals, and ironstones.

I. Calci{ertms Sa11dslo11e Series, forming two subdivisions. The upper, known as the Oil-Shale Group, is, in the Lothians, over 3000 ft. in thickness, and contains, in its higher part, beds of coal usually of inferior quality, and farther down, about six main seams of oil-shale, interstratified with beds of sandstone, shale, firecla,, marl, and estuarine limestones. The lower or Ccmentstone Group, ln which no oil-shales ha,e yet been found, consists of white sandstones and shales, passing downwards into grey, green, and red shales. clays. marls, and sandstones, with bands of argillaceous limestone or cementstone.

A well-marked volcanic zone. that of the Arthur's Seat lavas. lies between these two di,i,ions.

In the accompan)ing vertical section (Fig. 2) the various sub-di,;sions of the Carboniferous System of )1idlothian and Linlithgow-sbire are represented. but it ought to be clf'afly borne in mind that, evep ";thin the:;e limits, the rocks vary greatly in thickness from place to place.

The sedimentation in the Oil-Shale Group is espt'Ciall\ irregular, as the plate of vertical oection, at the end of this volume indicates, but it contains many pcrsi>tent beds which "

4 THE GEOLOGY OF THE OIL-SHALE FIELDS

rnTr---, -._

-._ l

1~ intermittent subsid-

Rtd ~-ts ence of irre$"ular amount, wberemcur-.. sions of the open sea

~od y~ Cotl-6dd J~. were extremely rare. Much of the sediment -s.....- ye must ha,e accumu-:; lated under mud-flat Cod

~ conditions. for sun-~SEAT l.J:nr.~ """" 1 cracks and ' desicca-Gu.ay l.oa:sto!tt t\\--.d tion breccias' are .Exnu. ~ ic0111 Socr.lt Pa-roc Co.J: commonh met with, "'"" ........,.,.. f:; especiaily in the

i! marly st r ata that Cor.h ~ L-o:at..-. l...oaabeld r ..... ~ 1_1,. ;,.,. H series .

II. DISTRIBl'TIO~ OF THE OtL-SHALES

ClUUll'l'Os LI.MUTO!II.t. -C.O.>s.uw)

~ suoo~

,_ .f;::;:;:;;;l

--~

-J;o;~ J"-'""='9

Flto\SElt Seu.l.a & Sbdl &d Although the R.un;a)l( S.u.u & SbcJl Ikd Calciferous Sand-llt.---rGu;. SK.t.u

l' >tone Series is well T~FoorCo.u. llooston M.uts GanStur..s developed in other HOtsro~ Co..t.

Ff:Ll.S SttAU: Al'CD Lut&ll'mr& !< harts of Scotland, it Jkoxbam NMts. ~r as not hitherto BJt.OX$l'L'l Stt.u.& Ck...ul.truclt.u:. Slu.u I~ yielded any oil-shale

" of cconom :c import-Ih:~":I"CT Stt.\t.X

J ~ ance beyond the BAilii-ACK$ LIWUTON~ aod 1\&JC limits of West Dwmtc Sa.udstooes n > Lothian, Midlothian, C.o~i'S S!Ut.lt ' B\""ltDlUO\l$& l.l'fUTO~I a and Fife. It is re-g markablc that though

P\. nt:u ro~ Sauu:s I i ~ bands of this material and Shell Bed are well developed s OA~.XOY Stur.c ,p along the western side of the Dalkeith """' s.oo,..,. r ~ basin, . they either " : occur m an attenu-w iUdie SJWe.;. a ted form dis-s or appear on the east Gtr.tco~ Alb:ybi!l 5lr.lts sode of that syncline. Attlllks Seat \'

6 THE G0LOCY OF TU O!LSHAL F!El.DS

dark blue shales or ' blaes ' often crowded with entomostraca. To the south-west, in the stream sections between Mid-Calder and Harburn, thick beds of blaes are again seen res~ on the lavas, and they are of pronounced Oil-Shale type, with thon ribs of ento-mostracan limestone and many beds of bituminou< shale or ' shaly blaes.' Further, none of the strata above are of the peculiar Cement-stone (or Ballagan) type, and from the lavas upwards, bands of oil-shale are not infrequent. It is therefore inferred that the base of the Oil-Shale Group should be dra"n at the top of the lavas, as it can be said that from that time onward, the peculiar phrsical conditions requisite for the formation of oil-shale had set in over the Lothians.

It is not contended that the top of the lavas is a rigid strati-graphical horizon, for it is quite possible that the Arthur's Seat eruptions were brought to a close shortly before those around Corston Hill and Cobbinshaw ; but it is held that there is a ~harp distinction between the types of sedimentation above and bclw the \'Oicanic rocks.

As will be shown presently, it is probable that the lowest oil-shale of commercial Yalue lies a long way above the lavas, but oil-shales are subject to such rapid lateral change that it is impossible to draw a base line for the productive part of the Group.

The Abbeyhill Shales are overlaid by the white and grey sand-stones of Granton' and Craigleith. From an economic point of ,;ew these sandstones are of great importanre, and the greater part of the 'New Town' of Edinburgh has been built of this material.

The Craigleith Sandstones are succeeded by a group of argillaceous strata, locally known as the Wardie Shales, which are exposed on the shore at Wardie and Granton Harbour. These contain several thick beds of poor oil-shale, along with entomostraca, fish remains, and (near the base of the series) a bed of marine shells. They underlie most of the new part of the city of Edinburgh, and arc laid bare in t he Water of Leith below Dean Bridge. In the tunnel of the London and North-Eastem Railway, between the Haymarket Station and Princes Street Gardens, a splendid sect ion of these beds was exposed in I893. and, during the progress of the tunnelling operation>. ~lr. H. ~1. Cadell examined the cuttings to ascertain if the strata included any material of economic importance. Consistin~ of laminated sandy shales. or' fakes,' argillaceous shale or 'blaes ";th ironstone nodules, hard ribs of ' kingle,' thin sandstones, and a few streaks of coal from I to 3 in. in thickness, the series contained no traces of workable oil-shale, coal, limestone, or ironstone. At various localities round Edinburgh seams of coal, I ft. or more in thickness,

1 In the' Geology of tbe )lcigbbourbood of Edinbul"@"b '( .. \!mr. G601. Sot..-., 1910, p. 53) tbe Abbcyhill Sbak$ were assign! to tb.e Cements ton~ Group.

"~An 18-in. dark laminated limestone c::ontaini~ shrimp&' (Teallris. ett:.;, fish remains, and occ:a.sional ~a.steroPOd.l . ~"awiUus. :tnd Orlltourt~s . """h discovered in 1919 bv Mr. D. Ta1t ncar lluirhou.ae bet'"n Granton and Cramond. This bed lies wen down in the Granton SandJton~. See Trans, Ed a,.. Geol. Soe., vol. xi., pan ii., I9lJ, pp. IJI-IJ4.

D!STRIIIUT!ON OF THE OlLSilALS 7

have been met ";th in the Wardie Shales, but none of sufficient value to be worked with profit.'

The Wardie Shales apparently pass underneath a higher set of sandstones extensivelv quarried at Hailes and Redhall, about 3 miles south-west of Edinburgh, and beds of inferior oil-shale rest on these strata. The overlying beds are imperfectly known, but it is clear that the Pumpherston Shales, which are the lowest seams yet worked, lie some distance above the Hailes Sandstones. From the Pumpherston position up to the top of the Oil-Shale Group, t he succession has been thoroughh ascertained from mining and surface evidence.

Recent investigations sugge>t that in the main shale area west of Edinburgh, the most easterly outcrop of the Pumpher>ton Shales takes place on the west side of the quartz-dolerite sills of Ratho and West Craigs, and that, with the possible exception of a small area N.E. of Ratho (p. 9-1), the whole region east of these outcrops is occupied by lower strata. These ba....al members of the Oil-Shale Group, as noticed above, certainly contain seams of oil-shale, but mostly of very inferior quality, as on the shore section at Granton. Since these seams are of scientific rather than of economic interest, they need not be considered here at length. A full de.cription of them has already appeared in the Survey ~lemoir on ' The Geology of the Neighbourhood of Edinburgh,' 1910, pp. 75 to 79. while analyses of several of the seams are given on p. 351 of the same publication.

Oil-shales of rather better quality are found in the higher beds, not far under the Pumpherston pooition, as on the coast section east of Queensferry, and at Dalmahoy south of Ratho; as they occupy the ground between Dalmahoy and Corstorphinr, this area may perhaps be productive in the futur~. but north or sou th of Corstor phine no good shale can be expected.

On the east side of the Pentland Ridge, in the Midlothian Basin, oil-shale was formerly worked at Burdirhousc and Straiten. by the Clippens Oil Company, but owing to protracted litigation as to anticipated damage to water-pipes belonging to the Edinburgh Corporat ion, the mines ceased operations in 1898. A narrow strip of productive shale measures probably extend all down the west side of the Midlothian Basin, for at leat one good seam has been found as far south as Carlops. In this region, like the coals in the Carboniferous Limestone Series above, the oil-shale,; dip at high angles, so that mining in these measures is both difficult and costly, and the shale must be of high quality to be extracted with profit. On the east side of the Midlothian Bain the oil-!'hales ha,e practi-cally disappeared. and no workable -earns have ever been found.

On the north side of the Firth of Forth, mining was at one time carried on in the Burnti>land di>trict. while ,hale-fwl

8 THE CEOLOCY OF THE OILSHAL FIELDS

in the Car boniferous Limestone Series of Scotland, and have been \\Taught at various localities either alone or as parts of seams of coal and ironstone. At present, however, not one of these can be con-sidered workable, and the oil-shales of value all occur in the Cal-ciferous Sandstone Series of the Lothians.

III. PHYSICAL CIIARACTERS OF LOTH IA' OIL-SHALE Oil-shale, as known in the Lothians, is a tine black or browni.,h

clay-shale ";th certain special features which enable it to be easily distin,guished in the field. Among Scottish miners it is termed ' shale,' and the stratified rock described by geologists as ' carbonaceous shale ' is distinguished as ' blaes, from the bluish colour which it often assumes, especially when decomposed into clay. This distinction is a convenient on~ in

10 THE GEOLOGY OF THE OIL-SHALE FIELDS

at Binny, this name has been sehx:ted to identify this horiLon. The material obtained from Hermand quarry is a first-etas> building

12 TBE GEOLOGY OF THE OIL-SHALE FIELDS

The Shell Beds.- Several bands of marine fossils, of great stratigraphical value in correlating between different areas, have recently been discovered in the shale-fields. The most im-portant of these are the Raeburn Shell Bed lving near the top of the Oil-Shale Group immediately under the Raeburn Shale, and the Pumpherston Shell Bed lying far below, close under the Pumpherston Shales. Both contain Orthoaras and goniahtes, but the Raeburn Shell Bed has a much richer fauna and the fossils are in a better state of preservation.

These bands have a very wide distribution. The Raeburn Shell Bed

1 has been found in borings in the extreme south-we~t

and north-west comers of the We..t Lothian shale-field, at Cobbin-shaw and Blackness respectively, and had previouslv been dts-covered, \\;th an identical assemblage of fossils, in the Fordell railway cutting near Inverkeithing (p. 99) ; it has bt:en traced in the Carlops district (p. 104) on the west side of the :\Jidlothian Bain, and was identied comparatively recently in the Strathawn di.O down the .\lidlothian Basin as far south as Carlops. and acros.' to Burntisland in Fife. Addit ional notes on these and other marin~ horir.on, will be found on pp. 107-108.

Two or three marine horizons occur in borings in the Cobbinshaw district above the Raeburn hand (p. 24). One of these, the Fraser Shell Bed, underlying the Fraser Shale, has recently been recognised in the cores of a boring near Blackness (p. 76)."

Lamellibranch bands are rare in the f.roduct ive shale measure~. hut are abundant ncar t he base of the Oi -Shale Group, between the Pumpherston Shales and the Arthur's Seat lavas. These basal beds also contain several bands of marine fossils, which are other-wise confined to the horizons mention~d above (see also pp. t\ and 107)-

- -of clastiC quartz and felspar. Tbe presence of a ftw comparatl\'cly lars:t" grams of quartz in such a fine sed.tment 1s difficuJt to explain. Th(' ca.rbonatt-t occur as very minute parttcles scattued throu~rh the clay conslttueat and as ag~regatcs of larger grains. and Jsolated rhombs 1ilhog crac_k~ and irregular spaces formed by shrinkage of the origmal mud, Both calcuc and dolomite are present; probablv also chahbite . Calcite predom.natcs 1n tht" iprcimen an'lfysed and probabfy in all the otben.

'The argillaceous coosutuent COnSISh~ m.llnJy of ~ric.tte, or .l cl~ly alhed mineral with which some hydro-aJumoou~ ~catc:-, such .._.., k.otolinue, haJiovsite, or aUophane, or a hydr.ue of alunnna. may be dUtX't.tt~. Stllca. in a f.:>rm other than quartz, and f~mc OXIde are abo J>f!~nt :

The ~tungle Shell Bed of he 2nd ed.luon of thts lfe:moir CJ9r!j ; su, bowe"-er. Summary of Progress of the CcoJO@'ical Sun"ty for 1913.' .\fem. Wei. Surt~., 1914, p. 102.

' Economic Geology of the Central Coali> or north-easterly trend. They constitute a system of trough faultmg on a large scale, for those two which are situated in the northern shale-fields have a downthrow to the south, while the other three throw down to the north.

The most southerly of these para llel lines of disruption is the Murieston Fault , which has a down throw lo the north and runs from near Baad's Mill, north of Cobbin~haw Hescrvoir, in a north-east direction by Murieston House towards Kirkncwton. That it must have a large amount of displacement is evident from the fact that, near Skivo, ahout 3 mi les south-west of Mid-Calder, it brings the Burdiehouse Limestone and a,;sociated strata on the north into contact with the lavas and tuffs of Corston and Linhouse Water, which have been correlated with the volcanic rocks of Arthur's Seat. Farther east, between Kirkncwton and Dalmahoy :.rains, it lets down the Oil-Shale Measuft'!; against the Cements tone Group.

The next dislocation is the Calder Fault, which has a nearly parallel course to that just described, with a smaller rlownthrow in the same northerh direction. At ~lid-Calder it truncates the basin of oil-shales on" the south, and tht're brings down beds over-lying the Broxbum Shale again~t strata below the horizon of the Pumpherston Shales--a displacement, prob..~bly, of about 1500 ft. The ground between Mid and We-t Calder i greatlv cut up by branches thrown off from thlS line of disturbance. South-west-wards the fault has been traced across the \\'e.t Calder field by Hermand and Little Harwood to the north of Baad's Mill, where it apparently dies out.

Still farther north we find tbe )hddleton Hall Fault, which C-'--tends from Seafield, past Dechmont, in a .:-I.E. direction to )tiddleton Hall. At the latter locaht\" II' trend becomes more easterly, and by means of bores and mining operations it has been

......

14 THE GEOLOCY OF THE OIL-SIIALE FIF.I OS

traced eastwards towards the Almond railwav viaduct. The amount of displacement at Middleton Hall, where beds not far belo" the horizon of the Cobbinshaw Limestone are brouf.:hl against strata associated with the Broxburn Shale, is about ~566 ft. Farther east, at Kilpunt, between Broxbum and the River Almond, the downthrow is about 84o ft. and the fault probably continu"" still farther eastwards beyond Corstorphine.

The other two important lines of disruption differ rom those already mentioned in ha~ing a displacement to the south or south-e..,'! instead of towards the north. The first of the>' an oval-shaped, smooth-backed knoll of yello,dsh tuff, containing baked fragments of the surrounding rocks. and shaped like an old hill-fort, Ranked on its

t )h. H.lt. Cadell now regard3 lhe ash bed, a1 \\'~t Sbore wood as con-nected with the Binns volcano, and not as mdcaun~ a separate '\"tnt. TFAws, Roy. Soc. EdtJls., vol. liu . pan a., IQ:l, p. lOJ .

16 THE GEOLOGY OF THE 011.-SHALE FIELDS

non hem, western, and southern

!8 THE GEOLOGY OF THE OIL-SHALE fiUD>

destroyed, and the strata reeking with oil, although there are only occasional sills of dolerite, a few inches thick, throughout the section.' In another boring (No. 418), by James Ross & Co., south of Philp-stoun. the plant remains in the blaes bed> were all carbonized and the oil-shale positions useless, for over 150 ft above a dolerite sill, whose thickness was not proved. In fact the exccnt of the altera-tion is apparently related to the length of time the igneous rock has been flowing between the bedding planes of the sediments, rather than to the size of the intrusion.

Contact -alteration of marls or marly blae:o often presents features of intere:.-t : in certain instances there are man, fe..t of hardened spotted marl on top of the sill (.g. on the Mons Hill dolerite at Whitehouse Point, in the Barnton railway cutting we't of Edin-burgh! or in the Sv.ineburn diamond bore near Humbie) crowded with small white spheroids set in a greenih matrix: at the same time the cement ribs in the marls seem to become more calcareous.

When the alteration is e>.-treme, beds of dark blue blaes mav be completely whitened at the contact with the i~eous rock : in such cases the dolerite itself is converted into ' whtte trap ' and greatlv decomposed (Duddingston diamond bores).

VI. DETMLED DESCRIPTION OF THE SHALE-FIELDS

1 . Cobbinsha.w Shale-field

(Edinburgh, II S.W. , S.E . and 17 N.W., N.E.)

The Cobbinshaw field lies at the extreme south-western limit of the Lothian Shale region: it surrounds Cobbinshaw Reservoir, and is bounded on t he north by the Murieston fault, on the west by the outcrop of the Cobbinshaw Limestone, and on the south by the Wilsontown Fault.

In one respect at least the field is unique, for the whole of the Oil-Shale Group outcrops within this comparatively small district. This long sequence of strata has been proved in recent diamond bores, and through the courtesy of those mtere.ted the Survey have been able to examine most of the cores in detail. This is a matter for congratulation, since the situation of the field makes it of quite exceptional interest from the stratigraphical point of \~ew.

The area has lately been the seat of exploration to determine bow far the oil-shale measures extend into the Lanarkshire Basin lying to the south-west. As this problem i:. of great economic importance, some general considerations on the question may here be discussed.

)lr. E. B. Bailev, reasoning by analogy from the bebanour of modtm basalt ta'-a tlows .,:uiTempest Anderson, Qufltt. Jot~r-n. G>>, S., 1910, vol lxvl .. p. 6.11\ makes the most interestmg S113&~t10n that 10 thrse C&.lte'~ tb~U> may originally ha'\-e been a lhtc::k mtroSJon of dolcnte which u~uenh mo"ed on. and ldt but a small renmant ~hind.

-:At Barnton these oonuct-ahcred marls c;ontatn t":ttnf-1 , docra-!oo(" . and ""'lla.stonite. Su 'The Gcologv of the !-le~hbourhood of Edmbur~:h, .\ltm, Gt:ol. Surv., 1910, p. 315. -

COUlllNSHAW SHALE-FIELD 19

The Lower Carboniferous rocks of the Central Valley of Scotland were laid down in a large basin, having an irregular floor of Old Red Sandstone and Silurian rocks. which kept above water for some time, in the form of ridges against which the earlier Carboniferous sediments were deposited. One of these banks of older rock runs past the south end of the Cobbinshaw field, as a continuation of the great Pentland Ridge. The proximity of tin> old shore line bas bad a ven serious effect on the productive capacity ?f the Cobbinsbaw field. Although the highest beds of the Oil-Shale Group, from the Cobbinshaw Limestone down to the Fells Shale, are quite normal, yet below this leYel there is not only a general attenuation of tile strata, but unfortu-natelv the shales themselves are affected. No \\~orkable shale has ever been found below the Fells, although the positions of the Broxburn, Dunnet, and Camps Shales can all be reco~ised.

Simi larly, in the Wilson town district to the south-west, the sequence down to the Raeburn Shale agrees perfectly with that in West Lothian, but some distance below that level a complete change sets in. This conclusion leads one to suggest that any future attempts to find ~hale to the south-west of Cobbinshaw and Tarbrax should be confined to the strata close beneath the outcrop of the Main or Cobbinshaw Limestone (see also fool-note, p. 5.)

The strata in the Cobbm Lime-stone Series. North of Cobbinin open-ing to the south, an anticline coming from the West Calder field intervening between thi> fold and the outcrop nf the Main Limestone (su Fig. j).

There are se,eral large fault,. two of which. one at each end of the reservoir, trend north-west and ha,e a downtbrow to the south-west. A con-tinuation of the east-and-we't Wilson-

~\

~ "Nllfl611YN

z oN 7D11

1

~ , . ., ~ ., . ~.... \ ' . \

~. I ..~

5l MYHSNIBBO:J

iC'Nuoll

,, ., I l

I I 'il ~ \

~ ~1 i~ 11/0AII'IIS:IJI

'Uti'HSNII/803

il ..;

~!

::: --~ ~

"" .E ~

:%

~

20 THE GEOLOGY OF THE OIL-SHALE FIELDS

Pumphuston ShaJ~.--A diamond bore, put down in 1907- tO by :\les.rs. Barr & Fraser, by the side of the bum x mile east of Har-bumhead Hill, started about 70 fms. below the Burdiehouse Lime-stone, probably just below the Pumpherston position. This con elusion is supported by the general attenuation of the strata in the Cobbinshaw field, and more particularly by the discovery of an encrinital limestone near the top of the bore. for no such bed is known in the Lothian Shale-fields above the Pumpherston position until the Raeburn Shale is reached. At 6z fms. the bore entered the Crosswood volcanic ash, which outcrops in the stream to th~ east ; 82 fms. below the ash anotlwr band of encrinital limestone was met with, resting on a dolerite sill. No shale seams of any value were found, and t he bore ended at 2o6 fms., just below three bands of entomostracan limestone. from 2 to 4 ft . thick. Lime-stones of this type are found 3 miles to the north, resting on the Corston Hill lavas, and it is practically certain that a few fathoms farther down the Ja,as themselves would have been met with, since they outcrop a mile east of the bore and were actually reached, at a depth of 130 fms., by the Camilty diamond bore, put down in 1912 near Halfway House on the Edinburgh-Lanark road. This boring also cut two sills; the upper one, 259 ft. thick, was reached at a depth of r6! fms., the lower one, 96 ft. thick, at 92 fens. Xo exJXl"ures of these si_lls are known, and they are therefore not re-presented on the foldmg map at the end of the volume.

Around Harbum, some 50 fms. of strata immediately below the Burdiehouse Limestone wer~ proved many years ago by chisel bore,, without result. The remainmg 20 fms., lving above the highest bed in )lessrs. Barr & Fraser's bore, probably contain the position of the Pumpherston Shales, but there is no reason whatever to believe t hat the shales would be workable, bearing in mind the condition of the overlying Camps, Dun net, and Broxburn Shales in this district.

The chief horizons from the Cobbin~h

22 THE GEOLOGY OF Tll Ol l.SilAl.E FIUDS

consisted of green and grey marls with bands of entomostracan limestone, limy cements, and sandstone.

In the Cobbinshawbasin, south-west of the Reservoir Hou,;e Fault, the upper shales appear, together with the Houston and Two-foot Coals. Cobbinshaw Reservoir occupies the centre of this fold, with the Fells Shale nearly 8oo ft. below the level of the water (Fig. 3).

Ftlls Shale and Limestone.-The lowest workable seam in this district is the Fells Shale; indeed it is the principal oil producer of the field, and has been wrought by mine.; both north and ,outh ~ the reservoir, and at Tarbrax. The Shale thickens towards th, west and south, being o,er 3 ft. thick in a bore nea.r Viewfield Pit _.;th 14 in. of 'wild shale' above, and 4 ft. south of Tarbrax; o~ the east side of the basin it is about 28 in. thick, with 8 in. of shaly blaes below. All o,er the field a band of cream-coloured or grey lime:."tone, with Spirorbis and entomostraca, lies below ~ ' ''e, affording an excellent index to the seam ; it is from 2 to , and is separated from the shale by 3 or 4 ft. of dark blaes "' .tsl:-remains, entomostraca, and small Lingula.

The strata between the Fells Shale and Houston Coal vary thickness from 13 to 2r fms. ; the lower figure occurs in the south part of the field at Lawhead. Farther north still, in the Addiew6 area, the thickness reaches 37 fms. These strata are mainly fake and sandstones with a little blaes, and no fossiliferous horizons II' known to occur.

Hr>uston Coal.- This coal at Cobbinshaw lies about 127 -" under the Cobbinshaw-Hurlet Limestone, as compared with 1 to 185 frns. at Addiewell. It is general ly a coal about 6 ft. thio. under the )fungle Shale South Cobbin>haw, 10! to 13 fm>. on )lorth Cobbin>haw, and

"out 23 fms. at Addiewell. ln the Cobbinshaw district it is ex "'Tllely poor (a few inches of coal and coaly blaes), but farther

.vrth it thickens a little and may reach 25 in. Jfungk Slud.e (Stewart's Shale of \Vc,t Cald~r ma).-This = was 20 to 24 in. thick at Addicwell, where it was wrought in

pits near the Breich Water. It is quite unworkable in lhc Cobbin "Gv field, averaging only S in. in six bores on North Cobbinshaw,

J.le three bores on South Cobbinshaw record 8, II. and IS in. ~low the shale come 2 or 3 fms. of blaes, but no marine shells have

oeen obtained at this horizon. , Mungle to Raeb14rn Shale.-Thc thickness of the beds intervening w.tween these horizons varies from 10 to 14 fms. in the Cobbinshaw

a, but increases to 20 fms. farther north at Hartwood and Addie . .:_ The beds consist mainly of blaes with a little fireclay and some

crayband ironstone ribs. Overlying the Mungle Shale comes or 6 fms. of blaes containing one or two shaly pli~s. and directly below the Raeburn Shale is the important index-horizon the Raeburn Shell Bed.

Ratbl4rn Shale and Shell Bed.-The Raeburn Shale averages 25 in. round Cobbinshaw ; on North Cobbinshaw it varies from r6 to 34 in., but has not apparently been \\TOught there. the shale worked as the ' Raeburn being probably the Fraser (su below) ; on South Cobbinshaw the o;eam formerly worked at a depth of 7 fms. in the pit situated soo yds. E.S.E. of the village school, was no doubt the Raeburn. The thickne,s in 9 borings in this area varies from 9 to 37 in. The Shell Bed immediateh underlies the Shale; the section in a boring on South Cobbin

24 THE GEOLOGY Ot' THE OILSIIALE FIELDS

The shells frequently show beautiful iridescent colouring, and arc in a remarkably fine state of preservation. A list of the fossils obtained is gi,en on p. ro8. This shell bed is "idespread in its occUllence, being found in the Imerkeithing clbtrict of Fifl', at Carlops in Midlothian, and at Strathaven (Lanarkshire). while what is almost certainly the same bed was obtained in a bonng at Black-ness below a post of shaly blaes which there seems to represent the Raeburn Shale.'

Raebunt to Fraser Shale.-Tbis distance varies from 13 fm~. at Greenfield to 16 or 18 fms.. on :\'orth and South Cobbin!\haw. while it reaches 29 frns. at Addiewell. The intervening beds consist chiefh of blaes "ith a few intercalations of ~.':>

The overlying blac> (alum-shale) contain small fossils bcami-flrlly preserved in pyrites. Locally a few inches of wild parrot coal with or \\ithout an inch or two of inferior ironstone rest imme-diately on the coal. The limestone itself, generally 5 to 6 ft. thick, is a dark-grey richly fossiliferous post. A curious vari ation in the typical dewlopment of the combined scam occurred at Woolfords, where a thin marine limestone was met with enclosed within the coal-scam itself. This occurrence has been described in detail bv Mr. H. R. J. Conachcr in the Transactio11s of lite It~stitrtle of Mini1tg E11gineers-' The section at the point where this li mestone was thickest is recorded by Mr. Conachcr as :

Fl. ln. AlumshaJe , . . . . . . , nbout ~ o Bright CoAL . . . . . . . . . . o 3 Dirt band with marine fos~ib . . o z ~odolar dark rnarirl c Ll\tMsTONE o Q COAL . . . . . . . . . . . 4 0

. The fo

26 THE GEOLOGY OF THE OILSHAI F FIELDS

stone. The sequence of strata is considerable, as the whole of the Oil-Shale Group above the Burdiehouse Limestone reaches the surface.

At the w1 It was this locality that was sclcc:ted as the -.ate tor tht c1~r Pr:lring .n search of oil put down in rqi9-1

28 THE GEOLOGY OF THF 011.-~HALE FIELDS

nating ";th ribs of hard cementstone ''arying in thickne

30 THE GEOLOGY OF THE OIL-SHALE FIELDS

south-west portion of this area is intersected by several east-and-west fanlts.

The Bu~diehouse Limest.,ne, which is exposed in the railway cutting at Blackmire, forms the eastern margm of this area. Here it is 40 ft. thick, and, after a short distance, is succeeded by nearly soo ft. of strata, composed of green felspathic

32 THE GEOLOGY OF THE OILSIIALE F IELDS

Young's 'Section of Addiewell' shows that 20-1 ft. of gre~n. brown, dark, and light marls "~th blaes and fireclay band, compose the Houston :\iarls and lie directly above the Grey Shaltc I hey are exposed in the Breich Water above Breich )Jill and are followed by the Two-foot Coal; this seam in the stream l:wlow Breichdyke i< 7 in. thick and is overlaid by black blaes " ;th sewral seams of good clay ironstone, followed by blaes, fakes, and firt.'Ch~-,... ";th occasional beds of sandstone. From the Blackbrae Fault the om-crops of this seam and of the Houston Coal ha "e a general trend towards X. !0 W. ; south of We:;ter Breich a ~mall anticlinal fold marks the soutberlv termination of the Dcchmont arch, which is so important a feature in the fields to the north (su p. 1.~). The strata between the Two-foot Coal and the Mungle Shale are here estimated to be 130 ft. in thickness. The latter ~am ,aries in thickness from 20 to 24 in., and was worked by >hallow pit> on both sides of the Breich Water, wh~>re it appear-; to be about 20 fms. below the Raeburn Shale.

The Raeburn Shak, the highest one wrought in th~ Addiewell district, was known here first as the 'Dam Shale' 1 and ubsequenlly as tlte ' Upper Shale of Addiewell.' The ;,ection of this earn at Addiewell is as follows :-

Roof, blaes c ~HALE, good

n soft ,. good

Sbal)' blaes Blaes and fu-eOuth of 6o fms., and can be traced cast aero"' the Hartwood field to the )lurieston Fault near Torphin. A parallel di-Iocation down 30 fm

34 THE GEOLOGY OF THE OIL-SHALF. FIF.I.OS

Fault, which runs parallel with the stream all the way. ~lost, if not all, of the strata certainly lie between the Burdiehouse Lime-stone and the Corston Hill lavas, but their exact position is doubtful for some distance south of Annetscross Bridge.

The section is of value on account of the evidence afiorded as to the lowest members of the Oil-Shale Group ; it is clear that true oil-shale conditions set in imroediateh: after the close of the lava period. and that the type of sedimentation, from thence onwards, was strikingly different from that in the Cementstooe Group below.

The Murieston Fault crosses the stream above Camp Bridge at Skivo, where green and brown sandstones lying on top of the Burdiehouse limestone are thrown against the Corston Hill volcanic rocks-a displacement of some 300 fms. Resting on the slaggy top of the lavas, at the bend below Skivo, is a thick bed of volcanic ash, with some sandstones interbedded ; overlying these ;, a mass of black blaes with several thin beds of platy entom~tracan lime-stone, associated with a good deal of shaly blaes. and some thin ash ribs. A short distance higher up the stream similar strata are again visible, accompanied by fireclay and clay ironstone bands. These strata, in all some ISO ft. thick, probably represent the Abbeyhill Shales of the Edinburgh district.

To the south-west, a long ascending sequence of arenaceous strata is met with, broken by several sma\1 folds and faults, of unknown size, running in a general south-westerly dir~~tion. The sandstones are grey, often coarse, with partings of greenish sandy blaes containing strings of clay ironstone; some darker banar\', and it is more in accordance with the character of the associated strata.

Farther upstream the ascending sequence continues, in a series of grey sandstones, sometimes massive and coarse, with partings of green sandy blaes as before. A curious bed of brecctated limy kingle is found at the top of the sand-stones, jUSt above the bridge at West _.~.,.J. I>:' -..I I Torphin, and opposite the farm stead- 771H NOSllo3[j ing a band of platy entomo~tracan limestone crosses the stream. Resting on this bed there are 20 ft. or more of dark blaes (? Pumpherston position)

, '

~~~i

.Jt_..,_:l

followed b\ sandstone with a con-glomerate -about 3 ft. thick, the ., pebbles consisting chiefly of red and t >: green felsite and chert. Beyond this "' ~ point the section is discontinuous. A !:! ~ thin limestone has been quarried about ~ ,_ ~ one-third of a mile to the south of ~ ~ ~ '-West Torphin, while a little higher up, ~ ~ ~ at the parting of the waters east of ~ [ ., Kiprig, the Burdiehouse Limestone ~ g 7;;oa has been mined, but no section is now .-: "' -visible at this point. "'

3. Alderstone, Bellsquo.rry, and Newpark District

(Edin&urgh, 5 S. W., S.E., and II N.W., N.E.)

This district includes the area that lies between Livingston and Wester )1urieston, the structure of which is rather obscure, chiefly o";ng to the thick covering of drift that conceals the faulted and plicated strata. A section line (Fig. 5) has been drawn from Limefield Mains quarry north-east to Xewpark, thence southwards to Wester Murieston. The '-arious positions occupied by the Burdiehouse Limestone within this district are represented to illu:.trate the highly folded character of this area. The section in the railway at Blackmire

... ~ ~ .... '< ~

"' ~!;1 ~~

~~ ....

~ ~ .. ~ ..

--1 ,, I

I I I \ \

\

i ~

:! ~ ~ ... ... !!

~~

~ ~ "' -~ -.l ~ ~ .... .

~ ~

ci (i;

has already been described (ue p. 30), and as the Burdiehouse Limestone and its overlying be&, exposed in the Harwood Water, are again repeated in the cutting, a fault "ith a displacement of at least 8oo ft. must intersect the ground between these two points.

Between Blackmire and Xewpark House a basin of the Burdie-house Limestone has been extenively quarried on both sides of the

l

36 THE CEOLOCY OF THE OIL-SHALE flELDS

public road which leads from the railway station to BeUsquany. On the west side of this fold the limestone is either at a high angle or tn some cases is slightly inverted, wlule to the south-east of Bellsquarry it ' forms a sharp synclinal fold on the north limb of which the beds are quite ,ertical and even a little inverted at .Bmcefield quarry' (Cadell, Trans. Edin. Geol. Soc., I9QI, vol. viii .. p. 142; Trans. Insl .. Uin. Eng., I9Qt, vol. xxii., p. 345). These quarries are now partly filled up, and this basin is separated by the Calder Fault from the other two depressions which lie on the south side of the railway. The section line (Fig. sl has been drawn across the largest of these folds as far as the Murieston Fault. Hen the limestone was originally worked open-cast , and was later won b~ a shaft, 37 fms. deep, near the centre of the basin. The stone, which is very pure, varies in thickness from 20 to 26ft., and was used entirely for smelting purposes by ~fessrs. Wm. Baird & Co., Cart-sherrie. 'Cndemeath the limestone is a seam of fireclay, but the ' Buckie fake,' wluch lies near the bottom of this fireclay at Camp;. quarry (p. 48), has not been found in thj,; working. This basin has nearlY vertical sides, and the excavations show that its bottom consiSts of a succession of smaller undulations. The southern ponion of this field is intersected by the Murieston Fault, and her~ the Burdiehouse Limestone is let down against the upper part of the volcanic rocks of Corston Hill. A branch of this dislocation runs in a north-and-south direction on the west side of Dresselrig, the downthrow being to the west.

Pwnpherst011 Shales.-Young's Oil Company have worked thf' Jubilee Shale of the Pumpherston Series in a rrunedriven 6ooyds. south of Alderstone, the shale cropping out in an anticlinal fold, of which the western limb has been proved by boring. About 330 yds. north by west of Brotherton a bore started on the crop of the Burdiehou.,c Lime~tOne, and proved the shales 86 fms. below. Further boring found the shale crop passing through Brotherton: to the north-west of Bellsquarry the strata are much disturbed, and are sharply folded, while there is at least one large fault, with a downthrow to the north.

There is e,ery probability that the Shales exist under the small troughs of the Burdiehouse Limestone round ~ewpark, and they probably outcrop on the west ton Shales. The fault is again seen by the stream south of Langside, where there is an excellent Stion of the Under Dunnet Shale, 6 ft. thick. In the floor of the seam occurs an inch of volcanic ash (Ba1Tacks Ash), and below arc sandstones, the limy entomostracan top of which represents the Barracks Limestone position.

The Lang>ide-Bia~kburn Fault, which marks the northern boundary of the field, has been proved in the Dunnet workings south and we:.t ol Lang>ide ; the Two-foot Coal i> seen nearl.v ,ertical, where this fault cro.- the Breich Water, south of Grange.

Ga:,ieside Field On tl1e north side of the Langside-Blackbum Fault, ~tw..-n

Gavieside and the Ri,er Almond, there is a broad basin containing the Dunnet Shales. This trough is a northerly continuation of that at Polbeth, and thr T.ang,ide Fault has a displacement at this point of 200 fms. At the Gavieside mine the )fain Dunnet varies from 6 to x6 ft., but its gemral working thickness is TO ft. A section here gives-

Roof, Su \ I L Top Su.\ll . pi lin .. SnAI1:,

38 THE GEOLOGY OF THE OIL-SHALE FIELDS

At the nonh end of the Ga";eside sptcline, se,-eraJ outcrops of dolerite are seen in the Rher Almond between the weir and the ford west of Livingston, where the Lower or Under Dunnet Shale (6 ft.) is seen by the stream, with the Barracks Ash and Limestone (at least 1 ft.) below, while the Main Dunnet seam was proved several years ago by trial pits. To the east of this weir marly strata, together with conglomerate bands and limy ribs of sandstone, arc exposed along the north bank of the stream.

5. Breiob She.le--fteld

(Mostly in Linlithgow, 9 S.E.; the sou/hem part in Linlithgow, I2 N.E.)

This field reaches from the Langside-Biackburn Fault south-wards to :\!id-Breich, where it is separated from the West Calder area by a fault running east and west, d0\\11 south 10 to zo fms.

Until comparatively recently, the structure of the ground wa,; obscure, as considerable folding occurs. Extensie boring opera-tions have been done by the Pumpherston Company, who have now opened up p;u-t of the field. Some boring has also been done by the Oakbank Company near Easter Breich.

The main axis of the Dechmont arch passes southwards through the field (see Fig. 6), and on the east side minor folds appear trend-ing in a similar general direction. The core of the chief anticline, east of Blackburn House, is occupied by the Dunnet Sandstone Group, and as the fold pitches to the south, successive outcrops of the overlying shales appear. On the west side of the arch, south and south-east of Blackburn House, the strata are at first very steep, and trial pits and borings found the Dunnet Shale almost verticaL The inclination of the seams lessens towards the west, the Broxburn Shale lying at 6o and the Fells Shale at 40. but it persists steadily, so that the Cobbinshaw Limestone and Coal are reached within half a mile, at the east end of Blackburn ''illage. Little is k-nown of the strata above the Fells Shale, although there are several old shafts to the Houston Coal, and near Hopefield ){tUs there was a day level to the Two-foot Coal.

On the south-east side of the main anticline thexe is a trough containing the Broxbum and Dunnet Shales, to which pits ha,e been sunk by the Pumpherston Company. Borings hereabouts indicate that the strata rise gently towards the south up to an arch in the Fells Shale at Hermand Oil Works, where both Felb and Broxbum Shales were worked out some time ago.

Little is definitely known as to the structure of the east ~ide of the field near Easter Breich; probably there are two sharp folds trending south-west, and separated by faulting, which bring up the Fells and Broxburn Shales to the surface (see Fig. 6). Beyond this troubled belt the strata dip steadily into the Polbeth basin.

There arc few natural exposures in the Breich field, but diamond bores have afforded good .ections of the strata between the Fells and Dunnet Shales. The general development is much the same

COUSLAXD Al~D SEAFIELD SHALE-FIELDS 39

as in the Deans field, though the Fells Shale is much thicker ; this seam has been extenshely wrought between Easter Breich and the southern boundary fault.

The Dunnd S114la lie in some 20 fms. of strata, consisting mostly of blaes; in the middle is the Main Dunnet Shale, 12 to 14ft. thick, with one or two parting:; of limy cementstone an inch or so thick. The Upper and Lower Dunnet Shales are poor and irregular.

The overlying Binny Sandstone Series, about 40 fms. thick, has several beds of green marl in the upper part, the sa.ndstones being poor ; lower down there is a good deal of grey marl, and bands of thin-bedded limy sandstones with brown ribs occur just above the Dunnet seams.

The Broxburn Shales are well developed, four seams, all close together, having been proved; one of them was 4 ft. 4 in. thick, but they vary considerably and appeat to thin towards the north-east.

The Broxburn !ll'arls are about 30 fms. thick, several limestone bands occurring as usual at the top of the series, under the Fells Shale. A section of the latter seam is appended below.

Sui ion of F tUs Shale at East~r Brtich

Roof, bla ... SRAI.t, plain

., curly .. , plain ..

Ball ply . SHAL', inlerior ..

Holing, blaes.

6. Ooualand and Seafield She.le-fields

(Unlithgow, 9 S.E.}

Ft. ln. 0 8

I II 0 6 0 6

4 9

These fields lie between the Deans and Breich areas; thev are bounded to the south bv the Langside-Blackbum Fault, which has a downthrow to south at this point of about 6o fms.

The area is bisected bv the Middleton Hall Fault, which has a down throw to the north o( 8o fms.. at Barracks, but increases rapidly towards the south-west, being some 150 fms. at Seafield : most of the mined area lies north of this fault.

The chief seams worked belong to the Dunnet Shales. and the general sequence is in agreement ";th that in the Deans field. The Broxburn Shales are considerably thicket, however, and lie only 20 fms. or so above the Main Dunnet Shale.

West of Cousland there is a small trough with the Houston Coal in the centre, and the Fells, Broxburn, and Dunnct Shales on the east side. On the west side of this fold a reversal of the dip repeats the outcrop of the Houston Coal, which is succeeded by the Two-foot Coal and the Raeburn Shale. These beds incline to the west, and pass under the Cobbinshaw Limestone to the north-east of Blackburn village. At Seafield Oil Works there is a sharp anticline in the Fells Shale.

4

,

10 THE GEOLOGY OF THE OIL-SHALE fll!LDS

In the north-west part of the field a small opening was made long ago in the Raeburn, or Dam Shale, south of Starlaw, and there are several old pits to the Houston Coal.

South of the :'.liddleton Hall Fault much of the ground is ob>cure. As yet only the west side of this area is definitely known ; here the Dunnet and Broxburn Shales have been worked, dipping west at 22. Borings found the Fells Shale only 12 fms. above the Broxbum. Otherwise the sequence agrees with Deans, the Dunne! Shales being fully developed ; one bore passed through the Barracks Limestone, 6! ft. thick, and then through nearly 42 fms. of sand-stone strata beneath (Dunnd Sandston~ Group).

East of Seafield there must be a broad antacline, for near Grange the Dunnet Shale is found dipping east into the Gavieside trough (p. 37). This anticline is really part of the long Dcchmont ridge, and is well seen in the Breich field to the south. It can hardly be a simple arch, judging both by the sharp folding of shaly blaes seen in the River Almond, about a third of a mile above its junction with the Breich Water, and by the abrupt folding north of Seafield Oil Works. )lost of this ground between Sealield and the river is probably occupied by the Dunnet Sandstone Group, in continuation \\ith that round Long Livingston. A valuable field of Pumphcrston Shales probably exists here, at quite workable depths, to Judge by the persistent westerly thinning of the strata under the Burdiehouse Limestone which is exhibited in the Livingston field; owing to the steep dip at the junction of t he Breich and Almond, they may even outcrop south of Cousland.

A greatly decomposed igneous rock is seen in the Deans Bum south of Cousland, possibly belonging to a neck, but its field relations are very obscure.

7 . Livingston and Deans Sb&le-6elds

(Linlithgow, 9 X.E., S.E. and 10 X. W., S. W.) These fields lie to the north and west of Livingston village. The

recent geological re,;sion (in 1912) led to an important modification in the sequence of strata in the district : the Barracks Shale and

uw- -~~ C.IIL-~: . ::

T4 ,t.L, .

~ ... ~" _ ....... ~,. ,,~ -

i; .. ..

Ftc. 7 .-Secli

.---------------~~~~~---~-----~------------~---.. f .. -42 THE GEOLOGY OF THE OIL-SH.UE FIELDS

Under the shell bed, dark blaes occurred with abundant remains of Tealliocaris, a shrimp-like form, but these striking little fossils are probably quite local.

The oore also gave evidence that there is a new oi l -shal~ position close under the shell bed, and this seam has also been proved to the south, in the Oakbank Company's oores near Dedridge quarry (see p. 47). All the strata, from the Pumpherston position doml-wards, gave ofi a stron~ smell of petroleum when scraped with a knife, oil-shale posit1ons hemg represented by strong dark blaes, "ith a deep brown streak. Curiously enough. no dolerite was met with at any point in the boring, nor were any of the plant remains carboniscd. A condensed summary of the journal "appended: the sequence should be compared with that proved at l>uddingston (p. 83).

~0. 25 BORE AT ~F.WYEAI{F!ELD, ~EAR l .TVI~CSTOI'>

THJCK;t.;J:;SS,

Fms. Ft. ln. Surf.-ce deposits Gr~v and white sandstone 1n bed .. , 'iOmc

cOarse. and bands of ~) marly blaes '"'h some sbaly blaes ne;or th underlie Livingston village as far as the River Almond. There IS no reason to suspect the presence of the Houston Wood dolerite sill, which has destroyed such large areas of Dunnet Shale to the north~!. In fact, the lowest or Under Dunnet Shale seems already to have been proved, for it is practically certain that this is t he shale found in a oore at Livingston Offices, a quarter of a mile north of the village. The section was-

BORE AT LIVDIGSTON OFFICES

l:xD&R Ouxx~"T SHALE Bbe. .. ..

B.\RRACXS LUIESTOX ..

Ft. ln. 3 6 3 0 5 0

The Under Dunnet Shale, Barracks A~h. and Barracks Limestone were proved in 1912 in the diamond boring close to Newyeartield already mentioned. A condensed journal shows :-

44 THE CEOLOCY OF THE OIL-~HAL HLDS

TtuCK!'\8~5. DIPTI:I FRO\t

SURYACl., . Fms. 1-'t. Jn. Fm>. Ft. ln .

Surface deposits .. 0 s 6 0 s 6 Dolerite . . . . 4 I 6 s I 0 Marls and marly fakes, baked l 0 7 7 I 7 )farly blaes . . . . . . .. . : 0 0 9 I 7 Dark blaes. '\\ith plants and abundant $14eria 2 s 6 I> Blaes, pyritous, with AUixopleria ftuduosa

and goniatite fra.gme.nts .. 0 0 3 ll I 4 Blaes . . . . . . .. .. 0 3 0 I! ~ 4 Strong black blaes "'--ith black streak :Eulteria

in top J ft.-C,.DER Dc~~T SHAL~ J.X>"l s tion) . . . . . . . . . . . . : j 4 I; I Sandstone fakes . . . . 0 I I I; : C) Limy cement . . . . . 0 0 10 " J 7 Soft yellowish rib of ash IB.ARJUCKS A..,H; . 0 0 I I ( 3 3 Blaes, with occasional entomostraca.. . . 0 j 0 16 0 ~ Lt\IESTO:-E, dark, entomostracan .. .. 0 0 10 16 I ti F aky sandstone .. .. 0 I 10 liS J ~ LT.)lSTO!'e Limestone) lies at the base of thts valuable group of shales. Fragments scattered about in the old quarry west of Barracks Farm show that it is a dark grey freshwater limestone of good quality, "ith a rou~h fracture; bores jn the vicinity show that it varies from 6 to 8 ft. 1n thickness. The overlying shale 1 (Under Dum.eJ or Barracks) rests almost directly on the limestone; it is variable in quality, and is not \\Tought to any extent. Bores record 3 to 6 fms. of fa.b.y blaes and f1reclay above this seam, succeeded bv the Main Dunnet Shalt, the latter from to to 4 ft. thick, and of excellent quality. A higher seam, known as the Upper Du>mtt, is partially mined, but varies con->iderably; it is separated from the mam 'hale by about 6 fms. of blaes, and occasionally attains a thickness of 6 ft. or mor~.

.-\bo,e the Dunnet Shales, the Binny San~tone Series is repre-sented by some 35 fms. of strata ; in the lower half of thi< group the Dunnet Marls, with ribs of brown kingle sands_tone and ~!"Y cement, are well developed, but in the upper part, m the posmon

1 Orig.inall) lmown as PaUlSOn's Shale.'

(

MIDCII LDER DISTRICT 45

of the Binny Sandstone proper, there seem to be no well-marked freestone beds, and the strata are faky and irregular.

The Broxbunr Shale group is not more than 5 fms. thick. Several beds of shale and shaly blaes occur here, but only one seam is being worked at present. The overlying Broxburn Marls show great variation in this field. In one bore, clo>e to Starlaw School, they were 21 fms. thick, but in two bores, situated about 200 yds. farther south, this was reduced to 10 fms. In the middle of the marls is a bed of coarse conglomeratic sandstone, while SC\eral beds of lime-stone are recorded in the upper part, close under the Fells Shale. The latter seam is thin, and is not worked at r,resent ; it is separated from the overlying H~" Coal by 20 to 27 m bet\\CCn the Hiver Almond and the Murieston Fault, and extend< from Crofthcad in the west to Raw Camps quarries in the east a dic;tance of 4 miles. The ground is bisected by the Calder Faull, south of wh ich the productive shale-measures do not extend, the ~longated strip between t he Calder and Murieston l:aults being occupied hy strata far below the P umpherston Shales, and even by part of the Cementstone Group (Fig. 9) .

The structure of the shale-Jxoaring area north of the Calder Fault is in continuation with t he Pumpherston field farther north. Tn the centre, west of Mid-Calder, there is a low anticline bringing up the Dunnet Sandstone Series, and on either side of this fold synclines are found, containing many "aluable shale seams (su Fig. 8).

The ~lid-Calder basin, lying on the cast side of the arch, has long been known, and is now ~orkcd out. It contains all three of the Dunnet Shales, together with a full development of the Broxbum Shales.

The westerly syncline, near ::\ewfarm, is ~he deeper of the two. It had always been suppo>ed to be shallow, wtth the Houston Wood dolerite. at the Dunnet ~ition, in the centre. Boring and mining operations by the Oak bank Compam ha\'e proved that the trough is a deep one, containing not onl~ the Broxburn and Fells Shales, but in addition the HoU>ton Coal and Marls. The X e"iarm basin is cut off to the south by a branch of the Calder Fault, throwing up the Pumpherston Shales approximately against the Broxburn-a displacement of 250 fms.

' Gp not publi

46 THE GEOLOGY OF THE OLLSHAL FLELDS J MID-cALDER DISTRICT 47

Burdielumse Limt$/4nt and Pumphersttm Shaks.-Near Croft-

) I . t ... I head, in the western part of the area, there is an old abandoned

~ ... ... "~ working (the Dedridge quarry) in the Burdiehouse Limestone . .,.~ ~ \

.. e . :~ .. .. ,. .. ' Fragments of the limestone can be picked up which show that ,,. fl) ;JNI),J.$/111/{):J ~ .. ~ it is of the usual type, banded and grey m colour. Resting ,,~ ~ '$W 'US ... .. v .. . ' ~.:!. on the limestone is a thin rib of yellow sandstone, above which -" .. ., ' " }: :: ., the Camps Shak, greatly weathered, can be seen, about 3 ft. 6 in. ; . .. " ~ ' l .. I thick. . ' .. .. , .. A diamond bore at this quarry, by the Oakbank Company, .. I proved the Pumpherston Shales 85 fms. below, and a further boring l ., ' i li ~ to t he south found another shale position 25 fms. lower still . 0 ~ ~ Between these two horizons is the position of the marine shell bed "1 : 3NO.J.$,W/'1 "/' ~ N~Nflll8177iWY1

~ noticed in the New~earficld boring, near Livingston (sup. 42) . " ' '-I ~ In the )lid-Cal er Basin, to the east, the following table pves ... the section of the strata proved by the mining operations o the ~ -~- .. = . ' ., .. ~ Oakbank Oil Company at Mid-Calder and by a bore sunk by that .. ~ ' "';; ... ... ~

I ~\ ~ .. ~ "" Company, in 18

48 THE GEOLOGY OF Tll OILSHALE FIELDS

This bore and pit section are situated near the centre of the basin, but the deepest part of the syncline lies farther to the cast, where the Burdiehouse Limestone is 1200 ft. from the surface.

In the River Almond, just above the railway viaduct, there is an excellent exposure of this limestone, where its thickness varies from 25 to 30 ft. The bottom portion is rather coarse, with chert bands and a Jumpy mammillated surface, while the upper beds are regularly banded grey limestones. From this point southwards to the Calder Fault its position is inferred from the proved outcrops of the Broxbum Shales. On the east side of the ~id-Calder basm between East Calder and the Raw quarri~. where the strata form an arcb, it was at one time extensively wrought. At Raw quarri.-, it occupies a synclinal fold about n8 ft. deep "~th a ,mall fault intersecting its western limb {ue Fig. 8). The basin is also tra\frsed by an east-and-west dislocation ";th a downthrow of 15 fms. to the north, the effect of which is to widen the trough in the latter direc tion The limestone was formerly worked openca~t round this area and burned on the spot for building purposes in the surrounding district, but in recent years was mined and rai~ to the surface by means of a shaft, and used entirely for iron-smelting at ("oat-bridge. Eastwards at Raw Camps quarries another synclinal fold repeats the Burdiehouse Limestone, where it occupies a complete basin 120 ft. deep and is inter,:ected by the east-and-west fault already mentioned. The limestone is 42 ft. thick, and rests upon its characteristic pavement- a band containing the small gasteropod. Platyost~>melJ.a scoi!Jbitrdigalensis, loc.~lly known as the ' buckic fake.' The stone was partly conveyed to the west for iron-,melting purposes and partly burnt at the quarries for lime. It is now entirely worked out all round its outcrop, while towards the centre of the basin, which was mined, only the sloofs now remain and the quarries are filled with water. On the top o this mined area there is a thick bed of dark blacs with calmv ribs and ironstone balls covered with boulder clay.

Camps Shale.- The blaes overlying the Burdiehouse Limestone at the Raw and Raw Camps quarries contains ' a scam of shale 8 ft. thick, yielding 22 gals. of oil ' (Cadell, Tra11s. Edit~. Geol. Soc., rgo1, vol. ,;ii., p. qz; Trans. lnst. Mi11. Eng., tgor, vol. xxii., p. 321). ln the River Almond section the blaes occupying the same position contains a similar bed of oil-shale, wbkh, in the )lid-Calder bore. is not represented.

The overl)mg Dunnet Sandstone Series is well exposed in the Rher Almond abo,e the railway viaduct at ~lid-Calder, the upper half of the section containing a good deal of blaes ,..;th numerous bands of bard limy cement and sandstone. showing ochreou.' weathering. In a streamlet fio..,mg down from the ,illagc into the river thin ribs of limestone and blaes, ";th entomostraca, represent the Barracks Limestone, and are covered bv several feet of yellowish green felspathic ash w~th ribs of limy kingle, belonging to the volcanic horizon also found in the Cra~gs diamond bore {su p. 55) and in the northern shale-fields. In this ~lion the ash ;, >Ucceeded by shaly blaes, doubtless representing the Under Dunnet seam.

MJOCALDER DISTRICT 49

Dunnet Shales.-ln the )lid-Calder basin the Under and ~ew Dunnet Shales were both worked, although of inferior quality to the Main Dunnet seam. In the Newfarm basin they are probably all burnt out by the Houston Wood dolerite, although there is a possibility that they exist intact in the deepest part of the trough.

Broxlturn Shales.-In the Broxburn suite of shales at Mid-Calder the upper seams were of good quality and the Curly and Broxburn seams excellent. At Mid-Calder the oil-shales of this group are slightly thicker than the corresponding seams at Broxbum, but the proportion of intervening strata is in the ratio of about 2 to I. Comparative sections are given below.

BROXBt;R.'I SHALE CROt;P

~fto~C.-\LOE.R. BROXBIJRS. Ft. In. Ft. ln.

SB-'-L ... \.\".E.&: .. I (> I I Strata 13 0 12 3

~~HALB 0 8 Sn.,LE BIG) . . 4 6 l LIMLSTO~ 0 6

SuALB I 6 Strata .. 12 0 3 10

S:RAt.'E ( LoWER BIG) 6 0 (CR&v) 5 10 Strata .. 10 0 s 4

SHALE (C1:RLY) 6 0 (CvRLV) 5 4 with' dirt J ft . .z in. Strata . . .. , 0 4 0

SHALE ,~I'LLAN) .. 4 0 BROXOURN) , 0 - - - -62 0 H 4

Ft. Ft. ln. Oil-shale .. .. .. Oil-halr . . .. 18 3

Stra1a .. .. 40 Strnla .. .. .. 27 - -62 H 4

The Shales and overlying marls can be seen in several fine cliff sections along the Linbousc and Murieston Waters opposite Calder Hall : in the former section there is a well-marked band of dark platy entomostracan limestone in the middle of the marls.

In the Ncwfarm basin the Broxbum Shales are thinner than at llid-Calder, but all the seams are pre~ent and arc of good quality.

Fells SIJale and H()JtsiM loal.- These beds arc only found in the ~ewfarm trough. The Fells Shale is here of very fine quality. and is separated from the Houston Coal by about 35 fmton llarls have been proved in boring, con-sisting whollv of green marl, with a few brown marl bands.

StraJa bekr.ll tJoe Pumphersum/osrtion.- In the Linbouse Water a small fault shifts the outcrop o the M' Lean or Broxburn Shale to the west side of the ~tream, and at the waterfall below Hoghill there is a notable section sho.,.;ng the great Calder Fault. The di,-place-ment must be at least 250 fms., for on the south side of the fault

I 50 THE GEOLOGY OF THE OIL-SHALE FIEtDS

all the strata lie some distance below the Pumpherston Shales; nevertheless there is surprisingly little disturbance of the strata. Immediately on the south side of the fault, a small dolerite dyke crosses the stream. About 300 yds. farther upstream there is another dislocation with downthrow to the north. Between the,;e two fractures the strata consist of blaes, pebbly and gritty sandstones, ";th bands of coaly blaes and ironstone ribs full of lamellibranchs. Southwards another fault is ~"isible in both the Murie-;ton and Linhouse Waters, and is apparently a southcrlv branch of the Calder Fault. On its south side there is a thick bed .of volcanic a$h and agglomerate, exposed on the west bank of the Linhouse Water, dipping eastwards, and in all probability this represents the a lent to this opinion by the fact that a diamond bore put down by the Oa.kbank Company, by the Yurieston Water 150 yds. to the north-west, went through 44 fms. of red and green limy marls, sandstones, and con-glomerates, similar to those seen below the lavas in the Lin house Water north of Corston Hill, and belonging to the Cements tone Group.

Overl)wg the ash in the Linhouse Water section, there are at least 50 ft. of shaly blaes .,.;th ribs of platy entomostracan limestone. and a few ashy bands interstratifted near the base. These are taken to represent the Abbeyhill Shales, and agree witl1 the strata resting on the ashy top of the lavas at Skivo (see p. 34 and Fig. 9). They are succeeded by a series of massive sandstones, with pebbly bands near the base, and in the centre some greenish sandy marls, a band of shaly blaes, and a dark limestone with plant

sz THE GEOLOGY OF THE OIL-SHALE FIELDS The Houston Wood dolerite t of the field west of Pumpherston, and must ha,e destroyed an enormous amount of shale.

Pwnphersron Shales.~n the west side of the main anticline, the Pumpherston Shales lie about 130 lm. below the Burdiehouse

~-

_ ,., .... ilt

MF""I'IA~''Iil

I

:,11.- Ur'i4 -?.~.!"'~ ... ~.... - ~-..,..._.~--.. -- """-~

t~"' ~.r:s-+ t~ ;; ~~ ODUiffTE ... ;s,~,

# MD~ l(H)(I,;::~~i'~- ...... ._ .. .,., ....... ._ ~ ! -- ___ ,, _______ -~------- --'f.l l:l/.01- ,.. ,.., I?S- Q, __ .., ,..,

- l ~.. ,~~..,,,..un.,.. -a .. ~ "--~-~ :~ ) !: ..:)t .. ~ .... ~ ~! :3 ;: ' .. '- .. ., ~~ ~ '~e-- -... 'li '!ii4 $" .. !.c- _ ... ~~-- - ::=:;--,, ---:.~- ....

r}~"' ''.. ....... _r .. :.t:,.~:,."";. ....... - --~' ... __ _ ---

FIG. 1 t.-Sedion auoulll' ctnlrt of llu PumpAcrstort Sltakfuld.

Limestone, the intervening strata being thicker here than in any other part of the Lothian Shale-fields. A little farther north, at the Roman Camp mines, the distance is about uo fms.

The seams comprising this group were at first worked open-cast, and afterwards mined to a vertical depth of over 1000 lt. from the surface. There are five workable seams contained in 92ft. of strata, as below.

SECTION OF PUMPHERSTO~ SHALES. Xo. r Mrs&- Pt:MI'HERSTO~.

Sbal Xo 0 {Hard calcareou~ band or limy rib c ... 1 r SHAlt. j1:BILE. :' '' '' . . . .

Blae~ . . , . . . . .

(Curly, 1ft, 9 ID.

Shale Xo. 2 or Plain, o ,, 5 .. I !t ~l,_'-YBRlCK seam. "lRib_, 0 , t , ,. S j 10

Platn, !. 0., . Blaes:, with balb .lnd nbs of Ltm) cementstone ..

Xo .. or .. curb,.. 1 2 ..

{

SHALE, pl.at~, I ft. I '")

Cu~v >SH.llE. ,. 1>Llin, I ,. 6 ,. fi II, St in. .. nb, 0 ,, + .. ,, plaan, J ,. 8 ,.

Fakes Blaes

Xo. _..or S PLAt'" SHALE, HALB

~0. 5 \V~ OT UNDE'R SHALl!:.

Rib . . Fakv bla~s .. Blais SHALE . Blaes and cemen l nbs SHALE

Ft. ln. 0 4 7 0

14 0

5 .1

'3 6i

7 H

16 7 5 5 7 g

0 r 6 I

1 s 6 10

4 3

PllMPHERSTON SHALE- FIELD

These seams gi ,.e a higher } ield of ammonium sulphate than any other Scottish oil-shales.

At the Roman Camp mines of the Broxburn Oil Co., the section is practi-caily the same as at Pumpherston.

The Maybrick seam has not been worked to any extent, but the others, especially the 'jubilee and Curly Shales, are of excellent quality. Veins of fibrous dolomite,' running both along and across the bedding, are a notable feature of tbe Jubilee seam, but are not found in the Curly ; the latter contains a bed 2 or 3 in. thick, in which fish remains occur in abundance and in fine presenation. Underneath the Wee or L'ndcr Shale ,-ery good impressions of 'ferns are found, Tel

54 TH. GEOLOGY OF TH. OIL-SHAL. FIELDS

Houston Wood dolerite, they must lie at least 250 fms. below the surface.

On the east side of the main anticline, the shales have been proved in deep bores by the Broxbum Company round Orumshore-land. Further borings by the same company near lllie.ton mdicate that the seams have been destroyed by igneous intrusons, as may be seen at the outcrop along the River Almond to the ea..t. They have not yet been proved under the Raw Camps limestone quarries, nor round Almondell or Clapperton Hall. There is a sharp anticlinal fold in the river at Almondell. which brings up to the surface some beds of shaly blaes with thin limestone ribs that are found all over the district about 40 fms. above the Pumphef'ton po and lime-stone.' At the north end of the arch, near Rval, the limestone has been proved, and again to the south, and doubtless it outcrops completely round the fold.

Pt::IIPH ERSTO)I SHALJ'-FII'I 0 55

Resting immediately on the lim~,ton~. one or more thin ribs of yellow sandstone are commonly found, and abo,e this 10 to 20 fms. of blaes, all more or les.~ shah-, but ('Spt'('ially "ly identified with the Barracks Shale) is workable on the we't side of the Pumpher-ston arch. where it is at pre.-;ent being wrought by the Pumpberston Company at Xo. 4 mine. The seam io; here 7 to C) ft. thick, with a fireclay pavement and shale roof. the qualitv vanin~ from good to medium.

On the east side of the anticline the seam dett>riorateo;, and has usually been recorded in bores a< ' shah blae' ' (Kilpunt and Drumshoreland). Round the south end of tht> arch it apparently disappears altogether, and ih poa.~t side of the Pumpherston anticline, where thev ha\'~ ~n worked in the Clapperton Hall trough, by the l'umphc,.,ton Co., tht> ~hales being vertical on the west side of the 'ynrline. The Under Dunnet (or Xo. 3 seam) ha.< ])('en proved northwards up to the )iiddleton Hall Fault, in a narrow extension of the Clapp

: s6 THE GEOLOGY OF THE OIL-SHALE FIHDS A boring put down by Young's Oil Co. in 1913 at Stankards, one-third of a mile south of Middleton Hall, also found the Shal~ badly burnt by the same intrusion ; in this bore a marine shell bed n in. thick, containing goniatites, Acti-J>teria. flu:lsa, and rare Ortlwuras, v.-as met with in the lower part of the burnt shaly material not far above the probable position of the Under Ounnet Shale. For 5 or 6 fms. above this Dunnet Shell Bed the blaes showed abundant Estheria (cf. p. 44).

BriCbum Shales.- In the south-east corner of the field an increase in the depression of the Clapperton Hall trough has let down a small area of the Broxburn Shales (Fig. 12). The Shales obtain their maximum development in the Lothians at this point, and in one boring no less than 6o ft. of shale were found \\~thin a distance of 23 fms., the strata being gently inclined, and the intervening beds consisting of shaly blacs and blaes with hard limy ribs. In this section the M'Lean, or Broxburn Shale proper, reached the extraordinary thickness of 28 feet, although it should be mentioned that subsequent mining proved this to be a ' pocket.'

All the seams are of high quality, as they are in the southerly continuation of the trough at Oakbank and Mid-Calder. There is a remarkable development of marl round Clapperton Hall. The Binny and Dunnet Sandstone Groups, which are respectively 40 and 45 fms. thick, have, as a matter of fact, very little sandstone strata at all, being almost wholly composed of marl with hard ribs of limy cementstone at irregular intervals. In the centre of the basin, about 20 fms. of Broxburn Marls have been proved in bores, the lower part being, as usual, greenish in colour.

Another small but valuable basin of the Broxbum Shales is present on the north-west side of the Pumpherston arch, near Loaninghill. The shales are not so thick as at Clappcrton Hall, but three seams have been proved, each 5 to 6 ft. thick, separated by blaes with limy ribs, the whole series occupying about II frns. of strata. The Broxburn seam in particular is of very fine quality.

Ori the east side of the trough the shales dip down at 45, and they are greatly contorted and overfolded, although still rich in oil. Bores show that there is a sill of dolerite in the Champfleurie or Lower Grey Shale position, xs fms. below the Broxbum. This ' ftoat' is well kno"n in the Broxburn field, and should not be con-founded \\ith the great Houston Wood intrusion, which comes 70 frns. or more below, in the Dunnet position: the current one-inch Geological Map (Sheet 32, 19xo) requires correction in this respect. There must be a fault between the outcrops of the Broxbum Shale and the Burdiehouse Limestone at this point, as they are only 400 yds. apart, and normally there mu.'t be at least t8o fms. of Strata between these position~. to which the thickness of the two whin sills must be added.

At Loaninghill the Broxburn Marl~ are 23 frns. thick ; at the 1 The upper sill, in the position of the Gre~ Sbal~. iot at Ic-u1 zo fms. I hick ;

the lower one which bas burnt the Dunnet ~b~l. waa. pro\"ed 1n the Slan-k:ards bore referred to above to be 34 fms. thick.

BROXBURS DISTRICT 57

top the Ftlls Silak ba:; been proved, but it is too thin to work at the present time.

10. Broxburn District

(LitolitJ.golll, 6 S. W., S.E.)

This area includes the Broxbum and Uphall fields, and is bounded to the south by the great Middleton Hall Fault, and to the north by the Eccle,rnachan and :-liddry Castle dislocations.

Tbe Broxbum Shales are here of \'ery fme quality, and are practically worked out, mining bci~ now carried on in the Dunnet Shale, of which large areas yet remam.

In the centre of the district lies the deeP. }{iddleton Hall trough, bringing down the highe.t beds of the 01-Shale Group. On the east side of the depression there is the well-1..-nown Broxbum anti-cline (su Fig. 13) in continuation \\ith the Pumpherston arch; to

; . .,~ ~ ... l ..,1.,, L71Vi:... ~ - ,: 3 .. ~ ,,..,,,u... ~ ... ~~ ... q, '"=: t-~ .. ;: l ~ .. . , :;

WI<

~~ '"" l ~=t: :::: ~--~ ' - * '9>; ; Si - f ;:;;:.~ .. t~. j ::-;,. " ..... .,..._.. -. -~~u. ~ .... ':~~~ .. ~--~::~ ~ ~,.r7"~--... . .. __ ., ~ .... - .,..i.4 FIG. IJ.-Seclion across the nortlrwn fuJrt of lit# Broxburn Sltalr-fitld.

2.-S. ~ 11; WIU, 6Mit ,-u!/1, 21'11'{ t:r :a:.., e -- - ~ -- ....

"" e"' !I~ ;~ \: ,. s: :~ ~ .~,~"' h ... = ~:t ,., Co "1: ~ "" ,- . - ~::!..-'~3 ~

.,,.J .. v..:~c;- -. :?~ ... . ) .. ;fr#t~rHMZ 'Mn( ' ~ :::~"":."',..._-... ........ .. ..

FIG, 14.-Se~i

! 58 THE GEOLOGY OF THE OIL-!'IIALE FIELng

Drmnd Shak.-A ~ingle scam of 'hale, from 8 to TO ft. thick, is found in the Dunnet !>O"ition, and ha~ been worked to the north and east of Broxbum, by two long mine!' dri\~n down from the Broxbum Shale. );ear Stcwartfield a dolerite sill lies close under the seam, this being an extension of the great Houston \\'ood intrusion of the Pumpherston field. To the west, beyond Uphall and Binny, borings show that the Shale is valueless, being repre-sented by strong dark blaes ; but there is no ignoous rock here-abouts which could have caused this deterioration.

A fathom or so tmder the Dunnct Shale there is a thin bed of grey or cream-coloured ' marly fakes,' probably a fine volcanic t urr (Barracks Ash), which is a useful index to the shale position: a simi lar mark ' is found to t he north, in the Philpstoun Shale-field.

No representatives of the New or Under Dunne! Shales are kn0\\11 in the Broxburn district, and the Barracks Limestone also appears to be wanting. In an old chisel bore at Stewarttield, several ' limestones ' are recorded clo'C under the Dunnet position, but the Barracks Limestone is ~ thin at Drumshoreland that it seems more probable that these belong to the series of hard lirnv cements and sandstones that commonly lie on top of the Dunnet Sandstones in other fields.

To the north and east of Broxbum, the Binny Sandstone Group is developed strongly, there being 50 to 6o fms. of sandstone strata in this position-a considerably greater thickness than at Binnv itself. Resting on the sandstone is the lMI!tr Grey or Champftturie Shale, found in several thin bands with partings of blaes. At Binny quarries these shaly beds contain abundant entomostraca. The seam is not workable at any point, and is succeeded by TO to 13 fms. of marl, on which lie the Broxbum Shales.

BroxlmrnShale:;.-Therc arc t hree valuable seams in this posit ion , with other thin shales above, the whole occupying 7 to 12 lrns. of strata. An average section has already been given on p. 49, in comparison with the sequence at Oak bank.

On the eastern limb of the Broxburn anticline the Curly Seam has been \\TOught to a considerable depth, and near East Mains it is rendered useless by the intrusive dolerite sill, which lies a short distance above it. ' At the mouth of the " Albyn" mine this intrusive sheet is in two thin bands and in close proximity to the shale. The lower one was found to he full of cavities coated with calcite. tilled in the heart with mineral "'-ax, yellowish-grey when fresh, and brown after exposure to the air. On analysing the hydrocarbon, Mr. Steuart, chemist, Broxburn, found it to consist of carbon (8435 per cent.), hydrogen (1283 per cent.), and nitrogen (r 68 per cent.), with traces of sulphur in some specimens. The shale was worthless near this rock, and the hydrocarbon was clearly derived from its distillat ion, and was subsequently accumu-lated in the cavit ies of the igneous material. ' 1

Identical phenomena recur in the lower silt found about the

1 I I. ll. Cadell,' Oil-shale Fidtl~ (')f lhe Lothians: Trans. lnst. .lfm. Et~~ .. IQOI vol. X1Cii., 1903 p .. 147.

BROXBl:Rl< DISTRICT 59

Dunnet !>O"hon, and the mines show that we are dealing \\~th two distinct floats.

To the east of Broxbum, beyond East )fains, the Broxbum sill, referred to in detail abo,e, lies in the position of the Broxbum Shales, which are consequently useless; but north of the village the intrusion ri'Cs a few fathoms into the overlying marls, and the shales are unaffected.

Broxb11rn Marls. T hese strata, comprising an unbroken serie.. of grey and greenish marls, vary from 20 to 35 fms. in thickness, and begin immediately above the lO,P shale (Upper Grey) of the Broxburn Series. The Felts Shale lies on top of them, but this seam, although constant, is too t hin to be worked with profi t at t he present time. The Broxbum Park diamond bore, put down to t he S.W. of the village, proved this seam, with the usual limestone band 7 ft. below, resting on the marls.

About 50 fms. of strata, mostly sandstones and fakes ,\ith beds of fireclay and blaes, separate the Fells Shale from the Houston Coal above, a:; proved by boring to the west of U,Phall. To this thickness there must be added a dolerite sill, which IS intruded into these strata, appearing in a series of rock knolls, running in a very regular manner between these seams as they curve round the Middleton Hall trough from Broxbum to lJphall. This sill, in common "~th the other two below, maintains much the same strati-graphical position for long distances. It was proved in the Broxbum Park boring, previously referred to, and the bore went down to the lower ' float ' m the Broxburn Shale position, and so cll'arly demon-strated the independence or these two intrusions.

Houston, Coal.-An average section of this seam in t he Broxbum field is as follows :-

CO,\L . BI.LC:t

Co.\L ..

Ft. l n.

J 5 4

0

The position of lht: 'earn is well defined by the line of the old crop pits, which can be traced from the Middleton Hall Fault to the ea--t of Holmes, thl'nce round the north and down the west side of the Fivcstanks basin to near Curledubs: traced in thi~ direction, the underh;ng dolerite sill is found to rise gradually, until to the north of Fivestank!. it immediately underlies the coal, rendering the seam 'blind' ~md worthless. Farther to the south the gentle upward transgr=ion of the sill continues, until at Uphall it overlies t he coaL

In the vicinity of Houston House, t he coal lies in two shallow basins (see Fill. 14). The seam first obtained its name from the workings in th1s neighbourhood, and proved in the J>ast >ufftcien lly valuable to supply this di-;trict with fuel. Forsyth, m his accoun t of the Houston Coal (' Mines, Minerals, and Goology or West Lothian,' Trans. High. and Agric. Soc. Scot., 1846), states that in the cast basin there were two pits, 22 fms. deep. The seam was divided by

6o THE. GEOLOGY OF TH~ OILSliALE FIELDS

a band of stone, 16 to t8 in. thick, the upper portion being a house hold and the lower an excellent smith\ coal. The total thickness was 5i ft., and 300 yds. from the bottom of the shaft the seam was 'blind '-a change doubtless due to the intrusion of the dolerite.

Hot~slon Marls and TfiJO{ool Coal.-These strata ha\e been proved in two bores, one of which, situated 6oo yds. N.W. of Five stanks, found the marls to be 35 fms. thick, with a few partings of blaes. On the top of the marls was the Two-foot Coal, as follows :-

Ft. In. Coarse SuA I.. and ironstone strains 0 s

.. B(..ACRBAND lltoN!)TOSR . , SHALE (g~) , . , .

, (iatr) . . . . Shal y blaes . . . . .. .. .. Co+.u. with strains of HLACKitANI> lRo~~TONtt

0 s 0 8 0 TO I 0

0 4

3 s Tllis composite seam was known at one time as the ' Fivestanks

Shale,' and a trial mine was driven in it from which a bore was put down to the Houston Coal.

Little is k-nown of the overlying $tTata. A bore situated near Middleton Hall Lodge went down 77i fms. to the Two-foot Coal, the strata consisting almost wholly of blaes "ith a few thin ribs of sandstone and clayband ironstone. Two shales were found, appar enUy representing the Raeburn and Mt~ngle seams. The latter lay 28 fms. above the Two-foot Coal, and consisted of 2 ft. of inferior shale with an inch of coal below. The Raeburn lay 33 fms. above, and was represented by 2 ft. n in . of shaly blaes, the intervening strata being all blaes wath clayband ironstone ribs, one of which was 20 in. thick.

ln this district the Raeburn Shale was at one time worked open cast to the south of Fivestanks, many years ago.

The highest bed of economic interest in the Broxburn field is a blackband ironstone which occun. in the basin round Middleton Hall, a section of which is giwn below.

BLACh."lJAND IRO!"STO,..; COAL and blaes B.B. lROSST0!-0

Fireclay ..

Ft. In. 0 l () l r r! 0 l

tO! A trial pit proved its thickness to be x8! in. Its position is

145 fms. above the Houston Coal, and the "topmost beds, which occupy the centre of this basin, cannot be very lar below the Cobbin-shaw Limestone. The estimated di~tance between the ironstone and limestone is 25 to 35 fms. 1

The Middleton Hall Fault must consequently have a displace-ment of something like 26o fms. at tllis point.

1 There is a 2-ft. shale re.slinf: on shaly blat'~ and lying 1 g fms. or so below tho Ironstone, wbicb may possibly repre.

r 62

r a " . ! ~ ..... . ~ .. ~ ~i

THE GEOLOGY OF THE OIL-~HALE tiUOS

~ tion, and the 'ibration l! produceOtl' train' which passed I '< daily through this exca-"I ~ ~~ vation, cau>ed fre{ucnt I fal.b from the rock aces. ~(~ ,-Cetion

' I~ \ was covered with I ~: ' I ; masonry. The map uscS of old I ~ :;~!! I ~ lim~'tone quarries \ I t;; ~~t---+ r I ., can

It 0!)~ , be seen on earh ide of \., :?~~ I ... the public road. 300 ydJ< . ,. \ l!' l

\ .,!; we5t of New :Mains, and /lln()J3"JOII \ I f* .. /113110, I ... again by the Niddry I ~

I Burn, 500 yd,, (ast of \ ; \ .,.;N JIIOB I~ Charles's Bri~c, on the \ ~~ east side o Ross's ~

' .i'"p~$ ,~

~ Plantation. Fragments

' ... ~ of dark banded limestone ' I~ ... of Burd iehouse type arc ' I~ .. I ' ~ ' li % found in abundance in I ~ ,. the ftrlds on t he site of I ~ "' I I~ ::! t he old workings. , 2 ~ ' I -I babh cut off to the Sotalt7.ed bumc about the Dunne! po near the surface almost as far as Duntarvie Castl

64 THE GEOLOGY OF THE OILSHALE FIELUS

Binny SandsiQne Group.-These strata are 55 fms. thick in the Swinebum diamond bore. and mostly consist of sandstone, but westwards thick beds of blaes, with some marl, are found in the lower portion. At the top are exce