P L A T E S A N D M A P S

IN ILLUSTRATION

OF

VOLUME V.

SECOND SERIES,

OF

THE T R A N S A C T I O N S

OF

THE GEOLOGICAL SOCIETY OF LONDON.

L O N D O N :

PRINTED BY R. AND J. E. TAYLOR, RED HON COURT, FLEET STREET.

SOLD AT T H E APARTMENTS OF THE GEOLOGICAL SOCIETY,

SOMERSET HOUSE.

1840.

E X P L A N A T I O N OF T H E P L A T E S A N D WOOD-CUTS.

Fig. 6, 7 and 8. Vertebrae, natural size: p. 352. Fig. 9. Chevron bone, natural size : p. 353. Fig. 10. Rib, natural size : p . 853. Fig. 11. Fragment of a coracoid : p. 354. Fig. A. represents part of the dental bone of Saurodon lanciformis, magnified three

times : fig. B. portion of the upper jaw and detached teeth of Saurodon Leanus. They are both taken from the plate which illustrates Dr. Hay's Memoir on the Saurodon. Amer. Phil. Trans., New Series, Vol. iii. p. 471. PI. XVI.

PLATE X X X . : p . 354.

Fig. 1 to 6 reduced to one-half, Fig. 7 to 12, natural size. Fig. I, la. Humerus : p. 354. Fig. 2. Radius : p. 354. Fig. 3, 4, 4a. Femurs: p. 355. Fig. 5. An Ischium : p. 355. Fig. 6. A Tibia : p. 356. Fig. 7, 7a. A Fibula: p. 356. Fig. 8 to 13. Metacarpal or Metatarsal bones and uncial Phalanges : p. 356.

P L A T E X X X I .

Illustrates the Rev. W. B. Clarke's paper on the Geological Structure and Phaenomena of the county of Suffolk, &c.: p . 359.

WOOD-CUTS

To illustrate Mr. Strickland's paper on the Geology of the Thracian Bosphorus: p. 385.

Section from Constantinople to Symplegades : p . 385. Section of a conglomerate near Filbornou, consisting of angular fragments of

trachyte, imbedded in a tufaceous paste and traversed by veins of calcedony : p. 389. Section on the north side of Anadoli-fanar: p. 392.

P L A T E X X X I I .

Map and Sections to illustrate Mr. Strickland's Memoir on the Geology of the neigh-bourhood of Smyrna: p. 390.

P L A T E X X X I I I .

Map and Sections illustrative of Mr. Strickland's paper on the Geology of Zante: p. 403.

P L A T E X X X I V .

To illustrate Mr. James de Carle Sowerby's paper on Crioceratites Bowerbankii and Scaphites gigas: p. 409.

Fig. 1. Crioceratites Bowerbankii: p. 410. Fig. 2. Scaphites gigas: p. 411.

E X P L A N A T I O N OF T H E P L A T E S AND WOOD-CUTS.

P L A T E S X X X V t o X L I .

Illustrate Mr. Prestwich's Memoir on Coalbrook Dale: p. 413.

P L A T E X X X V .

Map on the scale of one inch to a mile, the topography being copied from the Ordnance Map.

P L A T E X X X V I .

Sections, horizontal scale 2 inches to a mile. Fig. 1. Longitudinal section from the Wharf, near Lilleshall Hill, at the northern ex-

tremity of the coal-field, to Shirlot Hill. Fig, 2. Transverse section through Lilleshall Hill. Fig. 3. West and east section through Donnington Field. Fig.' 4. Transverse section from a little south of Hadley to Woodhouse Hill. Fig. 5. West and east section from Buckatree Hall to the Great East Fault. Fig. 6. West and east section from Wrekin Farm to Randley. Fig. 7. West and east section from a little west of Primrose Hill to Brans Farm. Fig. 8. West and east section from the Devil's Dingle to near Homer Farm. Fig. 9. Transverse section from a little south of Coalbrook Dale to Sutton Hill. Fig. 10. Transverse section from a little west of Benthall Edge to a little south of

Sutton Maddock. Fig. 11. West and east section from Wenlock Edge to Old Park. Fig. \2. West and east section from Westwood Common to Apley Park. Fig. 13. Diagonal section from N.N.W. to S.S.E., or from Cluddley to Dunvall. Fig. 14. North and south section from near Hadley to a little south of Willey. Fig. 15. N .N.W. and S.S.E. section through the Wrekin to the Severn. Fig. 16. West and east section from Henley Farm to Pendle&tone Rock.

PLATE XXXVII.

Diagram illustrative of the principal coal-shafts in their range from north to south, of the changes in the mineral composition, thickness and number of the beds; also of the nature and distribution of the organic remains. The vertical scale is to the horizontal in the proportion of about 26 to 1, in order to represent every bed.

PLATE XXXVIII.

Fossil Plants from the coal measures described by Mr. John Morris and engraved by Mr. James de Carle Sowerby.

Fig. 1. Halonia disticha, n. s. Length of specimen 4 feet; width from 4 to 6 inches. Stems and leaves unknown.

E X P L A N A T I O N OF T H E P L A T E S A N D WOOD-CUTS.

Stem ? internal structure unknown, replaced by sandstone. External structure; stem flattened, sinuous, with bifarious ascending protube-

rances, somewhat conical and obliquely truncated, the apex of each forming a nearly circular scar, with a depressed lateral cavity ; the side of each scar marked by a transverse depression; surface of the stem thickly covered with small oblong or irregular shaped projecting cicatrices, disposed in a quincunxial order, which become elongated and larger as they approach the protuberances.

In the older portions the cicatrices are less prominent. The resemblance of this specimen in some characters to Halonia has induced

us to place it in that genus; although it differs in the smaller number of protube-rances which are found on the surface, the bifarious position of which will at once distinguish it from all the other species.

Fig. 2. Bechera charceformis, (Sternberg, t. 55, f. 3, 5.) B. delicatula ? Sternb. t. 49. f. 2. Stem striated, jointed, verticillately branched, branches dichotomously whorled, leaves subulate.

This specimen is the same as Sternberg's figure, t. 55, and his B. delicatula ap-pears to be only an imperfect variety of the same species.

Fig. 3. Stigmariajicoides. The portion of stem of which the figure is a transverse section, is in more perfect preservation than the specimens of Stigmaria usually are found ; it is of a nearly cylindrical form, about 4 | inches diameter, the exter-nal surface exhibiting the usual markings of this curious plant j the internal part, with the exception of a vascular cylinder (also mineralized), being replaced by clay ironstone.

In the Fossil Flora, t. 31—36, are figures and descriptions of Stigmaria ficoides, and at t. 156 is shown the structure of the same; and although we cannot add much new information to that previously given by Prof. Lindley, it has been thought advisable to have another section represented with a view of showing what has hitherto not been well illustrated in the published figures of its structure. The internal cylinder in the specimen (fig. 3.) is eccentric, and consists of wedge-like portions of vascular tissue, the rounded origin of which, internally, is well-defined ; these wedges are generally of equal or nearly equal size, but they occa-sionally become confluent by the joining of two or more of them together. The form of the space necessarily left, or interstices between the sections where these are distinct, varies a little, in some cases being of nearly equal breadth through-out, and in others becoming narrower outwards and appearing to terminate or contract about the middle of the vascular tissue, beyond which they again fre-quently widen outwards: these spaces often contain portions of 'oblique and smaller vascular cords, apparently arising at different depths in the vertical cylinder; the origin and connexion of which with the cylinder is shown in the oblique section, where a single series of vessels is seen passing from it surrounded by tissue of smaller diameter. PI. XXXVIII . fig. 3 a.

In no specimen yet examined has the course of the oblique cords been abso-lutely ascertained, but there can scarcely be any doubt, as suggested by Mr. Brown (to whom we are also indebted for the above observations,) that these vessels after

3

E X P L A N A T I O N O F T H E P L A T E S AND WOOD-CUTS.

arising from the cylinder passed to the tubercles of the surface, through the thick cellular tissue which once probably occupied the larger space in the original plant. The discovery of these smaller oblique vessels is an interesting feature in the ana-tomy of Stigmaria ; and they have also been pointed out by Mr. Brown as ex-isting in Anabathra, and one of these is actually figured by Mr. Witham in his work1, but considered by him (p. 41.) as a section of a medullary ray. The ana-logous vessels existing in Lepidodendron Harcourtii, as figured by Mr. Witham2, appear to arise from the outer part of the vascular cylinder. A somewhat simi-lar arrangement is also found in that division of Lycopodiacece, consisting of Psilo-tum and Tmesipteris: in those genera, the vascular cylinder, from which the oblique cords proceed, includes a central pith3.

Fig. 3 b. Shows that the vessels are much smaller at the internal rounded portions of the wedges.

Fig. 3 c. Exhibits the oblique cords, consisting of smaller vessels surrounding vessels of larger diameter nearly equal to those forming the vertical tissue.

Fig. 3 a. Is an oblique section which exhibits the connexion of these vascular cords with the vertical tissue.

Stigmaria melocactoides, Sternberg, Flor. der Vorw. p. 38. Stem deformed, 6 to 8 inches thick, with the apex rounded, pertuse, and filled with

sandstone; leaves unknown, cicatrices like S.Jicoides. This I believe may prove to be a terminal portion of S.Jicoides. •

Sternberg considers Phytolithus verrucosus of Steinhauer, Martin, and Parkin-son as a synonym of this species; but it rather appears to be only a terminal por-tion of S.Jicoides.

Fig. 4. Carpolites Zamioides, n.s. The figure is somewhat similar to the Bothroden-dron pttnctatum, Fossil Flora, t. 218, and which is considered to have been a cone ; an opinion that can scarcely be entertained of our specimen ; the ovate and com-pressed form of which is more analogous to the seed of some species of Zamia or even Palms.

Fig. 12. Carpolites Helicteroides, n.s. Fruit ovato-lanceolate, attenuate at both ends ; polycarpous ?, Carpella 4 or 5, twisted spirally but not closely together.

The apparent resemblance of this specimen to the cast of a fruit of Helicteres has suggested the specific name, although its affinity to that genus may be very doubtful.

The above name was given to the specimen figured previously to our having S3en a somewhat similar fossil described by Presl in the last part of Sternberg's Flora der Vorwelt, where it is placed under the genus Palceoxyris of Brongniart, from its supposed resemblance to the inflorescence of the recent Xyris, an opinion scarcely borne out by the general appearance of this fossil; it has therefore been retained under Carpolites for the reason stated above. The two species already

1 On the Internal Structure of fossil Vegetables, 2nd Edit. t. 8, & 12. 8 Trans, of the Nat. Hist. Soc. of Newcastle, 1832. 3 Ad. Brohgniart, Hist, des Vege't. Foss. v. ii. p. 44, 45.

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E X P L A N A T I O N OF T H E P L A T E S A N D WOOD-CUTS.

Length 1 inch 4 lines, width 1£ inch. These casts have much the aspect of Mactrae; the hinge is unknown.

Fig. 3. Nucula cequalis. Transversely elongated, convex, marked with concentric ridges ; anterior side rounded ; posterior separated by a ridge and truncated; beaks nearest the anterior side.

Width twice the length, which is a quarter of an inch -, 3 a. is 3 b. magnified twice. Fig. 4. Nucula accipiens. Transversely oval, convex, concentrically striated; beaks

nearest the anterior side. Length 3\ lines, width above 4 lines.

Fig. 5. Nucula acuta. Transversely ovate, convex, concentrically striated, anterior extremity rounded, posterior extremity produced, pointed.

Length 1$ line, width 2\ lines ; 5 a. is 5 b. magnified twice. An elegant small shell.

Fig. 6. Unio Urii, (Fleming's British Animals, 417. Ure's History of Rutherglen and Kilbride, 311. t. 16. f. 4.). Transversely much elongated, very convex, wavy; posterior extremity rather pointed ; beaks near the small anterior side.

The general form approaches to cylindrical. Width 2^ times the length, which is about 1^ inch.

Fleming has confounded this with Unio ovalis of Martin (Petri/. Derb. t. xxvii. f. 1, 2.) which is quite distinct.

Fig. 7. Unio Ansticei. Very convex, wavy, curved, anterior side longest, forming a lobe ; posterior side obtuse, gaping ? Surface concave towards the front; beaks near the anterior extremity. -7 a. Reduced figure to show the front of the shell.

Length 1£ inch, width 2\ inches. This has much the form of a Mya.

Fig. 8. Unio parallelus. Transversely elongated, rather flattened, wavy; sides almost equally rounded; front and back straight, parallel; beaks near the anterior ex-tremity. 8 a. Shows the depth of the valves.

Length 1 inch 4 lines, width 2\ inches. Fig. 9. Unio dolabratus. Subquadrate, wider than long, rather flat with an oblique

convexity along the middle, even ; anterior side small, rounded ; the posterior side flattened and truncated; beaks near the anterior side.

Length 13 lines, width about If inch. Fig. 10. Unio modiolaris. Transversely elongated, convex, even, with an oblique

obtuse keel along the middle ; anterior side small, rounded ; the posterior trun-cated, flattened ; beaks near the anterior side.

Length f inch, width about twice as much. Fig. 11. Unio Phaseolus. Transversely much elongated, three times as wide as long,

even, convex; anterior side very small, pointed ; the posterior flattened, rounded. Length 3 lines, width 7 lines.

Fig' 12* Unio aquilinus. Transversely ovate, curved, flattened, rugged; posterior side pointed; beaks near the rounded anterior side.

Length half the width, which is 14 lines,

E X P L A N A T I O N OF T H E P L A T E S A N D W O O D - C U T S .

Fig. 13. Unio centralis. Transversely oval, rather convex ; beaks nearly central. Length 11 lines, width 17 lines. K

Fig. 14v Unio robustus. Obovate, convex, strongly marked with lines of growth, nearly as long as wide ; posterior extremity rather pointed.

Length 1 inch 5 lines, width nearly If inch. Fig. 15.. Modiola carinata. Obliquely elongated ; valves boat-shaped, deep ; anterior

lobe small. Length 11 lines, width more than ^ an inch.

Fig. \6. Mytilus triangularis. Triangular, with a rounded front, rather flattened, keeled towards the beaks.

Length 11 lines, width about 9^ lines. Fig. 17. Avicula quadrata. Quadrangular, convex, keeled; anterior lobe small,

pointed; front rounded. Length about an inch, width nearly the same.

Fig. 18. Avicula rnodiolaris. Obliquely elongated, compressed; keeled towards the beaks ; anterior lobe pointed.

Length 8 lines, width 4^ lines. Fig. 19. Pecten gentilis. Oblong, convex, smooth, with 15 slightly-elevated rays,

which are alternately long and short; ears middle-sized, equal. Length 5 lines, width 5 lines. A small neat shell.

Fig. 20. Pecten scalaris. Oblong, convex, concentrically striated, radiated, radii about 15, acute.

Length 6 lines, width 5 lines. Fig. 21. Spirifera bisulcata, (M. C. t. 494.) This specimen shows the impressions of

the internal spiral appendages, which, together with the long hinge-line, charac-terize the genus Spirifera.

Fig. 22. Globulus vetustus. Globose, smooth ; spire pointed ; umbilicus very small, open.

Height 11 lines, diameter 9 lines. Fig. 23. Littorina9. obscura. Oblong, umbilicated ? smooth? spire elevated; whorls

rather flattened on the sides. Height 14 lines, diameter 10 lines.

The specimens are imperfect casts ; they resemble the L. littorea, but are more elongated and have the whorls more distinct.

Fig. 24>. Turritella ? clavata. Turreted, conical, smooth; whorls about 8, flat. Height 10 lines, diameter 5 lines. This being only part of a cast, the genus cannot be ascertained with certainty.

Fig. 25. Turritella ? minima. Turreted, conical, ribbed; ribs obtuse, about 16 to each whorl; whorls about 10.

Height 7 lines, diameter 2\ lines. Fig. 26. Polyphemus ? fusiformis. Fusiform, smooth ; aperture half the length of the

shell, narrow; columella curved ? Height about 2\ inches, diameter above an inch.

E X P L A N A T I O N OF T H E P L A T E S A N D WOOD-CUTS.

This is the internal cast of a shell of a very unusual form,—we have referred it to Montfort's genus Polyphemus, as bearing the nearest resemblance to it of any we know. The curvature is possibly the effect of fracture.

P L A T E X L .

Fig. 1. TrochusX Usocona. Conical, with a broad base, marked with obscure concen-tric ridges; whorls about 5, their upper parts convex, the lower concave, with a broad band'in the hollow; edge of the base obtuse.

Height 2 inches, diameter nearly 3 inches. The broad band around this shell would lead us to place it as a Pleurotomaria,

did the lines of growth indicate that there ever was a deep sinus in the edge of the aperture.

Fig. 2. Conularia quadrisulcata, (M. C. t. 260. f. 3—6. Silur. Syst. p . 626. PI. XII . f.)

Many of the specimens in ironstone have smooth furrows between the crenated ridges, as shown at fig. 2 a., in others the furrows are crossed by striae, as at fig. 2 b., and both these forms may sometimes be found in one specimen, and arise from the presence or absence of a thin, dark brown skin or covering, the interior of which is smooth and the exterior wrinkled ; the ridges are often denticulated or notched. See ante, p. 44-2.

Fig. 3. Orthoceras scalpratum. Lanceolate, compressed, smooth, slightly curved, with the edges angular, the inner one sharp; septa numerous; siphuncle small, near the obtuse edge.

Diameter \\ inch. Fig. 4. Represents the interior of a small Orthoceras with numerous septa, and a

nearly marginal siphuncle. Fig. 5. 5 a. and 5 b. Nautilus clitellarius. Globose, umbilicated, septa numerous, much

bent in the middle, truncated and not recurved at the ends ; siphuncle central; umbilicus small, cylindrical; aperture above twice as wide as long.

The length of the aperture is 1£ inch, the width 2\ inches. Diameter of the shell 2\ inches.

Fig. 5. A front view of a specimen in which only a few chambers have been filled with ironstone, and it may be remarked that most of the specimens are preserved in the same manner. The whole of the shell has decayed away, and with it all the inner whorls have disappeared : the ironstone not having entered them, that por-tion of the ironstone which filled the umbilicus wanting support has been subse-quently broken and pressed into the cavity left by the shell. Fig. 5 a. is a lateral view of a similar specimen. Fig. 5 b. shows the remarkable curvature of the septa.

Fig. 6. Nautilus coneavus. Subglobose, umbilicated, concave on the front; septa slightly arched ; siphuncle central; umbilicus large; aperture, nearly twice as wide as long.

Length of the aperture 7 lines, width 1 inch. Diameter of the shell 1 inch 4 lines.

E X P L A N A T I O N OF T H E P L A T E S AND WOOD-CUTS.

The simple curve of the septa and concave front distinguish this Nautilus. Fig. 7. Nautilus subsulcatus, var. (N. subsulcatus, Phill. Geol. Yorks. ii. 233, in part.)

This appears to be the same species as the limestone specimen figured by Prof. Phillips; but as it has a shorter aperture, we have thought best to distinguish it as a variety. That author refers to Coalbrook Dale as one of the localities of his species, so probably he had seen the shell before us.

Fig. 8. Nautilus armatus. Discoid, strongly ribbed, ribs elevated into tubercles; septa numerous.

Diameter of the shell about 2\ inches. There is only just enough preserved of this shell to show that the septa are en-

tire, and that the ribs almost form spines; it much resembles Ammonites avmatus of the Lias.

Fig. 9. Nautilus falcatus. Discoid, inner whorls exposed; the front convex; sides nearly flat; the outer edge of each whorl obtusely angular, the inner edge inclined towards the preceding whorl, the space between crossed by many arched ribs; septa simply concave; siphuncle central; aperture nearly square, but 6-sided, with two of the sides very small.

Length of the aperture 1 inch. Diameter of the shell about 2f inches.

Fig. 10. Bellerophon hiulcus, var. (B. hiulcus, Fleming's British Animals, 338.) This differs from the specimens found in the mountain-limestone (M.C. t. 470. f. 1.), in having indistinct concentric striae crossing those which are parallel to the lines of growth, and in all the striae being sharper.

Fig. 11. Bellerophon Navicula. Globose, expanded, keeled, and flattened on each side of the keel, smooth ; columella solid, produced ; whorls rapidly increasing.

Diameter 5£ lines. The form of the aperture resembles the section of a boat, whence the name.

PLATE XLI.

Remains of insects and fishes: p . 440. Engraved by Mr. James de Carle Sowerby.

Fig. 1 to 4. Limulus anthrax. This fossil is considered by Dr. Milne Edwards to be

a new species of Limulus. Fig. 1 represents a nearly perfect specimen, with two of the legs extending from under

the body: in figures 2 and 3 the shield is believed to have been separated ; but Dr. Milne Edwards states that it is difficult to account for the three short horns exhibited by each specimen: figure 4 is a detached shield.

Fig. 5 to 7. Limulus rotundatus. This fossil is also considered by Dr. Milne Edwards to be a new species of Limulus.

Fig. 6 is the counterpart of figure 5. The membrane connecting the spines, and the circular outline of the animal, are considered to be peculiar.

Fig. 8. Limulus trilobitoides. (Buckland.) Fig. 9. Apus dubius. The only living animal to which Dr. Milne Edwards could refer

1

E X P L A N A T I O N O F T H E P L A T E S A N D WOOD-CUTS.

this specimen is the Apus corniformis, of the rivers of central and southern Eu-rope.

The remains represented in figures 1 to 7 are considered by £>r. Milne Edwards of great interest, as they exhibit characters intermediate between the living Limulus and the extinct Trilobite.

Fig. 10 and 11. Bones of the head of a Megalichthys. (See ante, p . 443.) Fig, 12, a tooth, and fig. 13, a spine, are assigned provisionally to the genus Hybodus;

the characters of the allied coal-measure genus Diplodus not being yet published by M. Agassiz.

Fig. 14. A tooth of a Cochliodus. Fig. 15. A spine, assigned with doubts to the genus Pleuracanthus, the state of

preservation of the specimen not being good. The spine is round but com-pressed, and is armed with two opposite rows of teeth. There are no traces in the specimen of the groove mentioned by M. Agassiz as one of the distinguishing characters of the genus.

WOOD-CUTS.

Fig. 1 to 4. Diagrams of the effects of faults in the coal-measures : p. 453. Fig. 5.- Diagram of the effects of lateral pressure produced by faults, from the Holy-

well pits, Malinslee: p . 454. Fig. 6. Section of changes of level produced by dislocation in the " best coal" Mea-

dow pits, Madeley: p . 454. Fig. 7. Diagram of a step-like dislocation at Priorslee, due apparently to unequal

hardness in the strata: p . 454. Fig. 8 to 10. Diagrams of complicated dislocations : p. 454. Fig. 11. Plan of minor faults and fractures inclosed between two principal faults',

the Boundary and Ketley : p. 455. Diagram of the minor faults which flank the Ketley fault near Donnington Wood fur-

naces : p . 456.

WOOD-CUTS

To illustrate the notice of Capt. Cautley and Dr. Falconer on the remains of a Fossil Monkey from the Sevdlik Hills : pp. 499-501.

Fig. 1 and 3. The Fossil Astragalus, natural size. Fig; 2 and 4. Astragalus of the Semnopithecus Entettus, natural size.

WOOD-CUT

Explanatory of Mr. Darwin's paper on the Formation of Mould: pp. 505, 506.

E X P L A N A T I O N OF T H E P L A T E S AND WOOD-CUTS.

P L A T E X L I I .

Illustrates Mr. Owen's paper on the Dislocation of the Tail at a certain point, observ-able in the Skeleton of many Ichthyosauri: p . 511.

All the tails represented in the accompanying plate belong to skeletons of Ich-thyosauri now in London and formerly in the collection of Mr. Hawkins: and these illustrations vrikl not lose force from the fact of their being taken from figures of those skeletons published without any reference to the structure or hypothesis in question.

Upper right-hand figure from a specimen found in the lias at Walton in Somer-setshire. (See Mr. Hawkins's work on Ichthyosauri and Plesiosauri: p . 32. PI. XVII.)

Lower right-hand figure, from a specimen found in lias at Lyme Regis. (See Mr. Hawkins's work, p. 25. PI. VII.)

Middle figure. , _ . _. , _. „_,, XT , . , v See the Second Part of Mr. Hawkins s work. ,} Left-hand upper figure.

Left-hand lower figure from a specimen found in lias at Walton in Somersetshire. (See Mr. Hawkins's work, p. 34>. PL XXI.)

P L A T E S X L I I I . to X L V .

Illustrate Mr. Owen's memoir on the Specimen of Plesiosaurus Macrocephalus (Cony-beare) in the collection of Viscount Cole: p. 515.

P L A T E X L I I I .

Reduced figure of Lord Cole's specimen, with comparative outline sketches of the paddles of Plesiosaurus Dolichodeirus and P. HawJcinsii: p. 515, et seq.

PLATE X L I V . : p. 518.

Fig. 1. Diagram of vertebral elements : p . 518. Fig. 2. Caudal vertebra of a Python : p . 518. Fig. 3. Cervical vertebra of a Pelican: p . 518. Fig. 4. Cervical vertebra of Plesiosaurus Hawkinsii, natural size : p. 523. Fig. 5. Cervical vertebra of Plesiosaurus arcuatus, natural size. Fig. 6. Section of terminal caudal vertebras of Plesiosaurus: p . 528.

P L A T E X L V . : p . 531.

Head of Plesiosaurus Hawkinsii and of Plesiosaurus Maerocephalus.

P L A T E S X L V I . and X L V I I .

Illustrate Mr. Malcolmson's memoir on the Eastern Portion of the Great Basaltic Di-strict of India: p. 537.

E X P L A N A T I O N OF T H E P L A T E S AND WOOD-CUTS.

P L A T E X L V I .

Map and Sections. The Map is intended only to assist the reader in following the description con-

tained in the paper, and to exhibit a general view of the distribution of the rocks occurring between the Taptee and Pennar rivers. However imperfect this slight sketch confessedly is, it is hoped, that by embracing almost all the information yet obtained respecting this extensive region, it will correct the erroneous opinion en-tertained by many, of the simplicity of the geological structure of the South of India, and afford a nucleus around which additional and connected observations may be gradually arranged.

It has been found impossible to employ more than two colours for granite, gneiss and mica, chlorite and hornblende schists ; for although many good obser-vations have been made on the distribution of these rocks in certain parts of the country, yet the boundaries have not, in general, been clearly distinguished, nor is it always easy to do so. Where the stratified primary rocks prevail more abun-dantly than granite, a purple tint has been employed.

The Diamond sandstone and argillaceous limestone appear to constitute parts of one formation, and it has therefore been thought better not to distinguish them in a map of such small dimensions; (hough an attempt to do so has been made in the sections. The laterite is introduced only where it occurs resting on basalt, at Beeder in the Deccan; its limits are unknown. Near Nellone, a nearly similar formation rests on the primary rocks, and is probably formed from their decomposition in situ.

The trap is represented the same colour as in illustrations to Col. Sykes's Memoir on the Deccan, (Vol. iv. PI. XXVI.) to enable the reader to connect the district represented in Col. Sykes's map with that contained in the accompa-nying map,

The section, fig. 1, at the top of the plate, extends from Bundlecund, beyond the north boundary of the map, to the Bangnapilly diamond-mines, situated be-tween the 15th and 16th degrees of north latitude.

Section, fig. 2, extends across the Peninsula from the coast near Atchera (lat. about 16°) to Madras.

PLATE X L V I I .

Organic remains collected by Mr. Malcolmson,and described and engraved by Mr. James de Carle Sowerby: p . 550.

Fig. 1. Chara Malcolmsonii. Oblong, spheroidal, with 10 ribs; three of the ribs are produced at the apex. Natural size and magnified.

This capsule is composed of 5 tubes, each of which is curled twice round. The figures represent a cast of the interior, the tubes being split down, and the outer halves broken away and left in the chert. The specimens are silicified and consti-tute almost the entire mass of the rock, in which they occur associated with Physce and Paludince.

E X P L A N A T I O N O F T H E P L A T E S A N D WOOD-CUTS.

Fig. 2. Cypris cylindrica. Twice as wide as long, almost cylindrical; front very slightly concave; the outer surface, which is very rarely obtained, is punctured.

Fig. 3. Cypris subglobosa. Subglobose, triangular, inflated ; front concave. The outer surface of this Crustacean is punctured as in C. cylindrica. Both species occur abundantly in grey chert, with the Unio Deccanensis and

other shells; and in various specimens of chert and indurated clay containing Gy-rogonites, Paludina, Physa, and Limnei, from the Sichel hills. The fossils are converted into calcedony.

Fig, 4 to 10. Unio Deccanensis. Transversely oblong, rather compressed ; margin internally waved; shell very thick ; surface finely striated. Fig. 6 is in limestone from the northern descent of the Sichel hills; the others are in chert from Munnoor. Natural size.

This species has often a ridge, which bounds the posterior portion, and is vari-able in size and elevation; it is most conspicuous in the limestone specimen, fig, 6, and in a cast in chert from Munnoor, fig. 7. Fig. 8 is possibly a very young indivi-dual, before the margin had assumed its wavy form. Fig. 9 is from a part of a group of many individuals of nearly one size, badly preserved in the same lime-stone as fig. 6 ; but as they are regularly oval, and do not show a waved margin, they may belong, as well as fig. 10, which is in grey chert from Munnoor, to a species distinct from U. Deccanensis. Some flattened specimens from this lime-stone are 2^ inches broad.

Fig. 11 and 12. Unio tumida. Transversely obovate, smooth, gibbose; posterior ex-tremity rather pointed ; beaks near the anterior rounded extremity. Natural size.

The section of the two valves united is regularly heart-shaped. The shell is rather thin, and it has something of the contour of Cyrena. It occurs in the same limestone with fig. 6, and the substance of the shell is replaced by cal-careous spar, which cannot be broken so as to show the hinge.

Fig. 13. Limneasubulata. Subulate, elongated, smooth; spine equal in length to the body; whorls five. In a nearly white, soft, siliceous stone, from Munnoor and Chicknee. Natural size.

Fig. 14, 15 and 16. Physa Prinsepii*. Ovate, rather elongated, smooth, spire short; body-whorl largest upwards. Fig. 16, in a soft siliceous stone from Munnoor. Fig. 14 in chert from Munnoor, and fig. 15 in chert from Chicknee; the drawing re-presents the shell as wider than it is. Many of the specimens are crushed. The largest, fig. 15, are 2\ inches long and upwards of an inch broad. Natural size.

Fig. 17 to 19. Melania quadri-lineata. Subulate, whorls about eight, with four striae upon each; aperture nearly round. Fig. 17, in grey limestone from the same lo-cality as 6 and 11. Fig. 18, in softish chert from Chicknee, associated with Physa Prinsepii. Fig. 19, in fine reddish grey chert, protruding from basalt near Munnoor, appears rather shorter in form than the others, but the spine is not perfectly exposed nor entire. Natural size.

* Mr. Sowerby has, with much propriety, named this fossil after Mr. James Prinsep, F.R.S., and Secre-tary to the Asiatic Society of Bengal; to whom Oriental science and literature are more indebted than to anv other individual.—J. G. M.

E X P L A N A T I O N OF T H E P L A T E S A N D WOOD-CUTS.

Fig. 20 to 23. Paludina Deccanensis. Short, conical, pointed, rounded at the base ; whorls 5 or 6, slightly convex, aperture round. Fig. 21 is in chert from Munnoor; and figs. 20 and 22 in indurated clay from between Munnoor and Hutnoor, the cavity of the shells being filled with calcedony. The young shell has a slight carina shown in fig. 20. Fig. 23 appears to be a crushed specimen; it is in laminated, indurated clay, Munnoor. This shell occurs, with Physa Prinsepii, in a beautiful green siliceous mineral at Munnoor; at Chicknee, and at the bottom of the Neer-mull pass. All the specimens natural size.

WOOD-CUTS.

Section of the Bangnapilly Diamond Mines : p. 541. Section of the Lonar Lake and surrounding rocks: p. 562.

WOOD-CUT.

Map of part of Mazunderan to illustrate Dr. C. M. Bell's Geological Notes of a Jour-ney from Tehran across the Elboorz Range to the Caspian, and back to Tehran along the course of the Heraz River: pp. 577, 581.

PLATE XLVIII. Map and Sections to illustrate Mr. W . J . Hamilton's memoir on part of Asia Minor

between the Salt Lake of Kodj-hissar and Caesarea of Cappadocia. The map is constructed from original documents. The descriptions engraved on the plate explain sufficiently the range and nature of the Sections : p . 583 et seq.

W O O D C U T

To illustrate Mr. Strickland's notice of some remarkable Dikes of Calcareous Grit, at Ethie, in Ross-shire: pp. 599, 600.

P L A T E X L I X .

Outline Map of part of the western coast of South America to illustrate Mr. Darwin's memoir on the connexion of certain volcanic phenomena in South America; and on the formation of Mountain Chains and Volcanos, as the effect of the same Power by which Continents are elevated : p. 601 et seq.

WOOD-CUTS.

Diagrams copied principally from Mr. Hopkin's memoir on Researches in Physical Geology, (Trans. Phil. Soc. Cambridge, vol. vi. pp. 45, 51.) to illustrate slow ele-vatory movements in the formation of mountain-chains : p . 625.

Diagram explanatory of the effect which would be produced if the thickness of the crust of the earth, upturned by elevatory movements, were equal to the distance between the anticlinal lines : p . 627.

PLATES L. to LVIII. Illustrate Prof. Sedgwick and Mr. Murchison's memoirs on the Physical Structure of

Devonshire, and on the Subdivisions and Geological Relations of its older stra-tified deposits : p. 633 et seq.

E X P L A N A T I O N O F T H E P L A T E S A N D WOOD-CUTS.

P L A T E S L. and LI .

Map and Sections of Devonshire and Cornwall.

P L A T E S LI I . to L V I I .

Organic remains engraved and described by Mr. James de Carle Sowerby. May, 1840.

P L A T E L I I .

(Fossils from Barnstaple.)

Fig. 1. Posidonia (Bronn.) lateralis. Compressed, transversely elongate-ovate, con-centrically ridged; umbones very near the anterior extremity; ridges angular. Width about CZ\ times the length, which is If inch.

Loc. Venn Lime Quarry, near Barnstaple. Fig. 2 and 3. Posidonia Becheri. (Goldf. Petref. 119. t. cxiii. f. 6 a. Bronn. Leonh.

Zeitsch. f. Mineralog. 1828, April, t. ii. f. 1—4.) Compressed, ovate, concentrically ridged, and finely striated; posterior slope

straight; ridges numerous; umbones nearest the anterior side. Width in pro-portion to the length as 7 to 4. Its length is about If inch.

Fig. 3 is from a specimen with fewer ribs. Loc. Venn Quarry. Swimbridge Quarry.

Fig. 4. Posidonia Becheri, var. (Goldf. loc. cit. f. 6 b. c.) Slightly convex, obovate, with the posterior extremity nearly square; concentrically ridged and finely striated ; umbones close to the anterior extremity. Width rather more than the length, which is nearly 1^ inch.

Loc. Venn Quarry. W e have seen specimens of this shell from Herborn, near Dillenberg, and Schelke

in Westphalia, where other species of the genus are also found. We can hardly believe this and the preceding to be the same species; but we

yield to Goldfuss, who has had more specimens to examine than have come under our observation.

Fig. 5. Posidonia tuberculata. Compressed, obovate, approaching orbicular, concen-trically ridged, and marked down the middle with three or four longitudinal ribs, which form more or less distinct tubercles as they cross the ridges. Length not %\ inches, and width full 2f inches.

Loc. The specimen figured is from Buddie, near Bamborough. We have examined one from Devonshire, which has the tubercles much more

strongly marked. Fig. 6 and 7. Orthoceras cylindraceum. A much elongated, smooth species, with ra-

ther distant septa. The specimens are too imperfect to be positively identified ; the name must therefore be considered only as temporary.

Loc. Venn and Swimbridge Quarries. Fig. 8 and 9. Goniatites carbonarius. Although we have seen many specimens of

E X P L A N A T I O N O F T H E P L A T E S AND WOOD-CUTS.

this shell, they have been mostly sections in various oblique directions, so that we have been unable to determine satisfactorily its shape or the form of its septa; all that we can ascertain is, that the general form of the shell is a depressed spheroid, with a large angular umbilicus, sinuated septa, and a smooth surface. It does not agree with any described by Count Munster.

Loc. Venn Quarry ? Fig. 9 represents, upon the same mass with a specimen of G. carbonarius, two small

individuals which resemble the G. stenolobus of Phillips, (Geol. of Yorkshire, PI. XX. f. 7-9.); but they are still more globose, have a finely striated surface and a small umbilicus.

P L A T E L I I I .

(Fossils from Barnstaple, Petherwin, Ilfracombe and Marwood.) Fig. 1 and 2. Pecten nexilis. Suborbicular, slightly convex, inequilateral, finely ra-

diated ; ears large, nearly equal, that on the anterior side less distinctly radiated than the other ; ribs very numerous, elevated, smooth, and thin.

A pretty species, of which we have seen only one or two specimens. It occurs with Leptcena caperata (fig. 4) and several other shells in slate from New Ifracombe near Barnstaple, and Barnstaple.

Fig. 2 is a magnified view of the same. Fig. 3. Pecten transversus. Transversely obovate, very slightly convex, radiated,

radii in threes, crossed by numerous regular lines of growth; ears large and nearly equal. Length about 1 inch, width nearly 1£ inch.

The great width of this shell is a prominent feature. Loc. Barnstaple.

Fig. 4. Leptcena caperata. Half-elliptical, very convex, concentrically wrinkled, spi-nose, margin not much deflected ; one valve very convex, the other almost equally concave; hinge-line rather longer than the width of the shell; spines adpressed, those near the hinge-line very long. The concentric rugae are lost towards the centre of the shell.

Loc. Abundant at Barnstaple and Petherwin ; also in New Ilfracombe Road, near Barnstaple.

This species a good deal resembles L. scabticula (M.C. t. 69, f. 1.), but is well distinguished by the numerous concentric rugae and the smallness of its spines.

Fig. 5, 16. Leptcena sordida. Transversely elongated, rather convex, irregularly striated, hispid ? muscular impressions occupying half the internal area; hinge-line nearly as long as the width of the shell, its angles rounded. Width variable, sometimes nearly double the length.

Of this shell we have but very imperfect specimens, and the exterior is badly preserved; the portions which remain show it to have been very irregular. These specimens have been inadvertently engraved with fossils from Barnstaple.

Loc. Linton. Fig. 6. Atrypa oblonga. Oblong-oval, convex, smooth; front produced, elevated;

the elevation narrow. Loc. Barnstaple.

E X P L A N A T I O N OF T H E P L A T E S AND WOOD-CUTS.

Fig. 7. Spirifera calcarata. Semicircular, with extended cuspidate smooth sides, sul-cated, very convex; front scarcely at all elevated; ribs numerous, rounded, with about nine on the front bounded by two deep furrows; area probably very narrow. Width more than twice the length.

This approaches closely to S. attenuata, M. C , but is distinguished by the sudden contraction of the sides, and the very slight elevation of the front; still we have some doubts of its being distinct from the many varieties of that species. The characters are taken from a single internal cast.

Loc. Barnstaple. Fig. 8. Spirifera disjuncta. This, which is a cast of the inside of the upper valve,

appears to belong to the species thus named, and is a good illustration of the in-ternal structure of the genus, exhibiting the beak, the muscular impressions, the central striated foramen, and also the hinge area with its striated structure.

For a further description, see PI. LIV. figs. 12 and 13. Loc. Barnstaple.

Fig. .9. Spirifera inornata. Fusiform, compressed, smooth, obscurely radiated on the sides; the front even; beaks obscure. Length scarcely more than £ of the width.

This is so much crushed and distorted, that it is impossible to give a full de-scription ; but it appears to be distinct from every other species, approaching nearest in form to the Orthis {Spirifera) alata of the Silurian System, PI. 22, f. 7.

Loc. Ilfracombe. Fig. 10. Orthisplicata. Transversely elongated, depressed, plaited; plaits numer-

ous, sharp ; width twice the length.

This resembles O. radians (Silur. Syst. PI. 22, f. 11), but has much more nu-merous plaits.

Loc. Barnstaple. Fig. 11. Orthis interlineata. A distorted cast, which may easily be mistaken for O.

canalis (Silur. Syst. PI. 22, fig. 8) or O. testudinaria (figs. 9 and 10).

Fuller details are given in the description of the Petherwin fossils, PI. LIV., Fig. 14., where better specimens are figured.

Loc. Leary, N . Devon, &c. Figs. \2—15. Calymene. Figs. 12, 13, 15, Barnstaple. 14, Saunton. Figs. 17—21. Crinoidal remains. 17, Barnstaple. 18, 19, 2\, Redruthen Steps, in St.

Eval. 20, Lower St. Columb, Perth. Fig. 22. Avicula Damnoniensis. Obliquely ovate, with a square projecting ear, very

convex, short, striated ; anterior side small, obtuse; hinge-line rather shorter than the width of the shell; beaks large, convex near the anterior extremity; poste-rior slope and ear destitute of the fine longitudinal striae which ornament the rest of the shell.

Abundant in the soft ferruginous sandstone in which the fossils of Marwood Quarry are all imbedded.

Fig. 23. Cucullcea unilateralis. Obliquely ovate, gibbose, smooth ; posterior side ob-lique, flattened; beaks nearest to the anterior side.

The cast,figured shows the impression of the internal lamina peculiar to the genus.

1

EXPLANATION OF T H E P L A T E S AND WOOD-CUTS.

The species is very abundant. Loc. Marwood Quarry, where the shells of this and the following species of

Cucullcea are often replaced by quartz. Fig. 24. Cucullcea Trapezium. Transverse, obtusely trapezoidal, oblong, irregularly

convex, smooth; anterior side rounded; posterior large, truncated, and longer than the rest of the shell. Length about f ths of the width.

Loc. Marwood Quarry. Scarce. Fig. 25. Cucullcea angusta. Squarish, rather wider than long, convex, smooth; an-

terior side rounded, the posterior truncated, square ; beaks central. A cast has the impressions of the lateral teeth, which confirm the genus. Loc. Marwood Quarry.

Figs. 26, 21. Cucullcea Hardingii. Transversely oval, with the posterior side trun-cated, gibbose, smooth, nearly twice as wide as long; beaks nearest the anterior side.

Loc. Marwood Quarry. Fig. 21 is an end view of a smaller specimen. Fig. 28. Pullastra ? antiqua. Transversely elongato-ovate, slightly convex, concen-

trically striated, striae distant; posterior extremity slightly and obliquely truncated. Length about £ the width.

Loc. Marwood Quarry. Fig. 29. Leptcena prcelonga, Obovate, longer than wide, convex, with a depression

along the middle, coarsely and irregularly striated; beak of the larger valve in-flated and overhanging the smaller one, which is concave; margin much deflected ; hinge-line shorter than the width of the shell j a few slight concentric waves pro-ceed from it.

Loc. Croyde Bay, in a harder stone than the Marwood Bay fossils. Fig. 30. Bellerophon globatus. (Silur. Syst. PI. III. fig. 15.) We can perceive no

difference between this fossil and some specimens from the lower beds of the old red sandstone.

Loc. Marwood. Fig. 31. Crinoidal casts abundant at Croyde Bay.

P L A T E LIV.

Fig. 1. Auicula (Monotis, Bronn) subradiata. Obliquely ovate, with one rectangular ear smooth, with a few concentric lines, and radiated principally along the middle; one valve flat, the other convex; anterior extremity rounded, small. Width con-siderably more than the length.

Loc. Petherwin. Frequent. Fig. 2. Avicula Pectinoides. Suborbicular,flattish,radiated; ears very large, square;

the posterior slightly sinuated. This specimen, which is very imperfect and worn, resembles A. Neptuni. (Goldf.

Pet. CCXVI. fig. 4), but wants the numerous concentric striae which ornament that

E X P L A N A T I O N OF T H E P L A T E S AND WOOD-CUTS.

species. We possess fragments which retain this structure, but are not sure they belong to the present species.

Loc. Petherwin, Barnstaple. Fig. 3. Leptcena Fragaria, var. If this fossil be referrible to the species described in

PI. LVI. figs. 5, 6, it is a very strongly-marked variety; but we are not satisfied that it is a distinct species, although the tubercles are more elongated—allowance must be made for the state of preservation.

Loc. Petherwin (abundant). Fig. 4. Atrypa hispida. Transversely oval, compressed, furnished with concentric

fringes of spines. Loc. Petherwin.

Fig. 5. Atrypa decussata. Subglobose, slightly compressed; front even, straight; surface concentrically striated and decussated ; beak of the lower valve very little prominent, with a trifling angle on each side.

Loc. Petherwin. Fig. 6. Atrypa indentata. Transverse, obovate, with an indented front; the edge of

the lower valve elevated; its beak small, prominent.

The front of this shell appears as if impressed by the finger, whence its name : the elevation in the margin of the lower valve does not affect the surface of the other; this may serve to distinguish it from A. obovata (Silur. Syst. PI. VIII. fig. 9), to which it bears a very close affinity.

Loc. Petherwin (with the last, abundant), Barnstaple. Fig. 7. Atrypa subdentata. Orbicular, slightly convex, rather longer than wide, with

a pointed three-plaited raised front; beak minute. Loc. Petherwin.

Fig. 8. Atrypa Unguiculus. Hemispherical, rather wider than long, with an inflated beak, smooth; front emarginate; lower valve very convex, its beak channelled; upper flat, with a central impressed line.

This pretty shell occurs abundantly in the Petherwin strata, and is very cha-racteristic of them; it is frequently twice the size of the specimen figured.

Loc. Petherwm, Barnstaple. Fig. 9. Atrypa triangularis. Triangular, with two folds in the front, beak scarcely

prominent. Very much crushed and distorted casts in soft ferruginous stone. Loc. Petherwin.

Fig. 10. Atrypa striatula. Suborbicular, convex, finely striated. A large species.

Loc. Petherwin, Barnstaple, Fowey ? Fig. 11. Spirifera externa. Fusiform, convex, radiated ; about 7 ribs 'are elevated

in the middle of the upper valve ; its beak small; radii numerous, commencing along the hinge-line.

Loc. Barnstaple, Barnstaple Bridge, Saunton, Petherwin. Figs. 12, 13. Spirifera disjuncta. Semicircular, with an emarginate front, very con-

vex, radiated ; upper valve with about 12 ribs, much raised in the front, forming 3

EXPLANATION OF T H E P L A T E S AND WOOD-CUTS.

a rounded elevation ; ribs rounded, numerous, about 25 on each side the middle; beaks remote; hinge-area broad, curved, its edges nearly parallel.

This differs from S. bisulcata (M. C. t. 494, f. 1) in its less convexity, more numerous striae, and broader hinge-area; and from S. bisulcata of Phillips (Geol. of Yorkshire, PI. IX. fig. 14), not of M. C. (which it very nearly resembles), in the greater regularity and number of the ribs *.

The specimens of this shell are so generally distorted, that its true form is seldom to be clearly made out; and this, added to the difficulty which already exists of determining between the most perfect specimens of different species, renders it very difficult to ascertain to what species they belong. Perhaps even the S. gigantea from Tintagel (PI. LV. figs. 1 to 4) may be distorted individuals of this species.

Loc. Barnstaple and Petherwin. Fig. 14. "Orthis interlineata. Suborbicular, compressed, with the front straight, finely

radiated, marked with lines of growth interrupting the radii, which increase in num-ber towards the margin; larger valve not very convex; its beak but slightly pro-minent ; the smaller valve with a shallow depression; muscular impressions nearly parallel in the convex valve, impressions of the hinge-teeth in the other, broad.

This species, when its internal structure is considered, forms a link serving to connect five species already described in the Silurian System. In the irregularity of its striae, and apparently wide form, it approaches O. lata (Silur. Syst. PI. XXII. fig. 10); in the depression and hinge-teeth of the lower or flatter valve it re-sembles the O. orbicularis of the Upper Ludlow (PI. V. fig. 16), and O. canalis of the Lower Silurian (PI. XX. fig. 8 ) ; and these species are the exact analogues of the O. lunata of the Ludlow (PI. V. fig. 15), and the O. testudinaria of the Caradoc (PI. XX.-figs. 9, 10): all of which, by a careful study of their internal characters, may be at once decided upon when all other characters fail.

Loc. Petherwin (abundant), Leary, N. Devon, Barnstaple, Morebath, Land-lake, Cornwall.

Fig. 15. Atrypa fallax. (Ter. pleurodon. a. Phill. loc. cit. t. xii. figs. 25, 26.) This species so exactly agrees with specimens of an Atrypa we have from Preston by favour of W. Gilbertson, Esq., that we cannot doubt its identity; and this appears to be a shell that Professor Phillips has united with several others, under the name of Ter. pleurodon; it is, however, a genuine Atrypa, though so like the genus Terebratula that we have designated it fallax.

Loc. Petherwin, Barnstaple. Fig. 16. Pleurotomaria aspera. Conical, short; whorls convex with a rounded keel,

marked above the band by four principal, and as many intermediate ridges, and beneath it by several smaller ones, all crossed by sharp laminae, which produce a reticulated surface; band narrow, reticulated.

* The Terebratulites aperturatus (Schloth. Nachtr. t. XVII. fig. 1) differs from this species in having a strong rib on each side the depression in the lower valve, and in possessing a triangular area. It is abun-dant in the Eifel, and much resembles the shell before us.

EXPLANATION OF T H E P L A T E S AND WOOD-CUTS.

A handsome shell an inch in diameter. Loc. Petherwin; Landlake, Cornwall.

Fig. 17. Terebra nexilis. Subulate, acute, longitudinally striated; whorls flat; striae gently bent twice.

A neat shell, much resembling Rissoa Lefebvrei (LeveiHe* in Mem. de la Soc. G^ol. de France, vol. ii. part 1, p . 40, PI. II. fig. 25)j but the striae are finer, the shell more elongated, and the sides of the whorls flatter, than in the specimens we have examined of that fossil.

Loc. Petherwin (frequent). Fig. 18. Goniatites vinctum. Discoid ; inner volutions two-thirds exposed; sides of

the whorls flat; their inner edges abrupt; front rounded, encircled by a thread-like keel; inner whorls crossed by straight undulations ; lobes of the septa three on each side, that on the middle of each side by far the longest; ovate, pointed.

The specimen before us, though very imperfect, is clearly distinguished from G. Henslowi (M. C. t. 292), by having but three instead of four lobes on each side ; and from G. subarmatus, (Munster, Plan, und Goniat. Tab. VI. f. 2.) to which it is closely allied, by the ovate form of the lobes, which in that fossil have their sides straight, and the whorls in that species do not increase so rapidly.

We have had the good fortune to see, in the Rev. Mr. Williams's rich collection of Cornish fossils, several new and interesting species of Goniatites and Cly-menia in company with a species resembling Nautilus (Goniatites ?) complanatus (M. C. t. 261.), which he has however reserved for future publication.

Fig. 19. Clymenia (Endosiphonites, Ansted) Icevigata. (Planulites lavigatus, Munster, Plan, und Goniat. T . I. f. 1.) A large smooth shell, with many whorls, and only a slight sinus on either side of each septum. Our specimens are not so large as that figured by Count Munster, nor is the wave in the septum placed so near the front of the whorl.

Fig. 19 a. Clymenia linearis. (PI. linearis, Munst. loc. cit. T. II. f. 5,6. Endosiphonites carinatus and minutus. Ansted Camb. Phil. Trans, vol. vi. PI. VIII. f. 1, 2, 3.)

This well-marked species is abundant in the Petherwin beds, and is distinguished from the preceding by the deep acute-angled sinus in the side of the septum, and also by its striated surface and linear keel.

Having examined the Cambridge specimens, we can see no reason for supposing the E. minutus a distinct species, especially as we have found on it the charac-teristic keel of E. linearis, or for altering the original specific name given by Count Munster.

Loc. Petherwin. Fig. 20. Orthoceras striatulum. Rather rapidly tapering, ornamented with prominent

transverse rings, crossed by numerous fine threads, which alternate with still finer lines ; annulations sharp, oblique, rather more distant than the septa.

This has a close affinity with Orthoceras Tubicinella of the Plymouth limestone (PI. LVII . f. 29.); but the threads are closer and finer, and it appears to be a larger species. At first sight it looks much like C. annulatum (M. C. 1.133.); but the longitudinal lines, and want of transverse scales, easily distinguish it.

E X P L A N A T I O N OF T H E PLATES AND WOOD-CUTS.

Loc. Petherwin. It appears to be abundant, and very variable in size. Fig. 21. Orthoceras. This specimen, though very imperfect, was figured on account of

the very curious longitudinal mark which crosses the edges of the septa, giving it the aspect of the alveolus of a Belemnite.

Fig. 22. Orthoceras. A remarkably crushed specimen, so as to resemble a form of Belemnite common in the Lias. Similar occurrences are not unfrequent in the Upper Ludlow Rock of the Silurian series.

Figs. 23, 24f. Fragments of two species of Calymene. Fig. 24 much resembles C. tuber-culoid (Silur. Syst. PI. XIV. fig. 4.), but differs from that species in the number of lenses to the eye, which are but few in the present specimen. Similar frag-ments are not very uncommon in a soft stone at Petherwin.

PLATE LV.

Figs. 1 to 4. Spirifera gigantea. Convex, radiated ; sides cuspidate; radii numerous, proceeding from the hinge-line ; about nine or ten are elevated in the front, which is deeply emarginate ; lines of growth rather conspicuous, crossing the ribs.

This magnificent species, which occurs nearly nine inches wide in micaceous slate at Tintagel, seems to be intermediate in character between S. disjuncta PI. LIV. f. 12, 13, and S. calcarata, PI. LIII . f. 7. The specimens we have examined are all destitute of shell, and the casts are covered with plates of mica, which lie flat on the surface and give it a glittering aspect; and they are so distorted in the direction in which the slate has been pressed, that they may easily be taken for many different, species. The ribs are about as numerous as in the S. Verneuillii, and are very regular.

Fig. 1 is a specimen pressed laterally and flattened ; a cast of the interior of the lower valve, natural size.

Fig. 2 is a young individual, showing the outside of the same valve; natural size. Fig. 3 is a specimen of the same valve, reduced to half its length. Fig. 4 shows the upper valve laterally compressed, and folded down upon one of its

sides; natural size. We have already given our opinion that this may be the S. Barumensis, but the

cuspidate sides may probably entitle it to rank as a distinct species. Loc. Tintagel.

Figs. 5 to 7. Spirifera costata. (S. speciosa of the Eifel ?) Elongated-fusiform, con-vex, costated; costae prominent, thick, about five or six on each side the middle, in which two are elevated and approximate ; lower valve with a deep broad depres-sion bounded by two strong ribs; hinge-area broad, its edges parallel. Length not | t h of the width.

The specimens we have seen of this fine Spirifera are all imperfect, and we cannot speak with certainty as to the surface ; lines of growth appear to cross the ribs, but they may be plaits occasioned by pressure.

Occurs with groups of corals, fragments, &c , in a soft slaty stone at Fowey, and at Tintagel in a hard blue slate with the former species, and at Looe.

EXPLANATION OF T H E PLATES AND WOOD-CUTS.

Fig. 8. Part of the pelvis of a crinoidal animal.

Occurs in a hard, flinty, slate rock, traversed by veins of Quartz at Looe.

PLATE LVI.

Fig. 1. Corbula Hennahii. Transversely elongate-ovate, with a slightly projecting beak, smooth, convex, valves somewhat unequal; posterior side obliquely trun-cated, anterior pointed; twice as wide as long.

There appears no likelihood to us of this shell being referrible to the genus Lembulus, to which it was assigned by Dr. Leach; its unequal valves, if this be not accidental, indicate its affinity to Corbula.

Loc. Mount Wise. Fig. 2. Cardium aliforme, var. (M. C. t. 552. f. 2. Goldf. Petr. 213. Tab. CXLII . f. 1.

Pleurorhynchus minax and aliforme of Phillips, Geol. of Yorks. 210. PI. V. f. 27. Bucardites hystericus, Schloth. Nachtrage. t. XX. f. 1.) One of the many varieties of C. aliforme. Goldfuss has done well in keeping them all together. We can see no reason for separating them into distinct species, or for adopting a new generic name.

Loc. Stonehouse Hill. Fig. 3. Leptcena analoga. (Phill. loc. cit. PI. VII. f. 10. Producta anomala, Sowerby.

See Encyc. Metrop. loc. cit.) The worn specimen before us we presume to belong to this species. We have seen a most beautiful internal cast from Barnstaple in the collection of the Rev. D . Williams.

Loc. Plymouth, Barnstaple. Fig. 4. Leptcena rugosa, His. ? (Dalm. Act. Holm. 1827, 106. Tab. I. f. 1.) We refer

this shell with uncertainty to Dalman's species, of which we have not seen well-authenticated specimens; its more even form distinguishes it from L. depressa. (M. G. t. 459. f. 3.)

hoc. Plymouth. Fig. 5» Leptcena Fragaria. Hemispherical, with slightly projecting sides, concentri-

cally waved, nearly smooth, pustulated; beak of the convex valve pointed ; hinge-line rather shorter than the width of the shell.

This species approaches very closely to Producta pustulosa (Ph. loc. cit. PI. VII. f. 15.), or perhaps more nearly to P. rugata (Ph. PI. VII. f. 16.); but, wanting the deep concentric rugae which mark these species, we have called it Fragaria, from the collection of pustulose tubercles (probably the bases of spines) which cover its surface pretty regularly; it is however highly probable that all are varieties of one species.

Loc. Plymouth, Petherwin ? Fig. 6 is probably the young of the preceding species; the tubercles are more numerous

in proportion to the size. Loc. Plymouth.

Fig. 7. Leptcena interrupta. Semicircular, very gibbose, concentrically ribbed ; longi-

E X P L A N A T I O N OF T H E P L A T E S AND WOOD-CUTS.

tudinally and finely striated ; striae interrupted by the concentric ribs; hinge-line equal to the width of the shell; beak somewhat produced.

A small species, nearly akin to L. punctata (M. C. t. 323). Loc. Plymouth.

Fig. 8. Atrypa juvenis. Broad-ovate, slightly convex, smooth, curved, longer than wide; front somewhat pointed; valves nearly equal, the lower curved upwards with a minute beak.

A small, rather flat species, distinguished by its narrow front, and by being curved.

Loc. Plymouth. Fig. 9. Atrypa lacryma. Subglobose, smooth, longer than wide; front straight or

slightly waved, scarcely raised except at the edge, which is deeply sinuated by the projection of the inferior valve, the central furrow of which is broad, flat and bounded by two sharpish ridges ; its beak not prominent; side rounded.

An obscurely-marked species ; very convex, and with nearly equal valves. Loc. Plymouth.

Figs. 10, 11. Strigocephalus (Bronn) giganteus. (Terebratula gigantea, Sowerby. See Encyc. Metrop. loc. cit.)

Suborbicular, convex, smooth, with a straight pointed beak ; valves nearly equal; area beneath the beak a right-angled triangle, flat; foramen narrow.

Almost all the specimens we have seen of this noble shell, which is often six inches in diameter, are much distorted; its true form appears to be round. It very nearly resembles the genus Atrypa, but differs from it in the presence of an area between the beaks ; this species is distinguished by its small straight beak, and its flatter shape, from the Strigocephalusporrectus, which is plentiful in the Plymouth limestone, and is (Ter. porrecta, M. C. t. 576. f. 1.) Strigoc. Burtini of continental authors.

A specimen with a slight depression along the lower valve we once distinguished by the name of Ter. Hennahiana (see Encyc. Metrop. loc. cit.), but subsequent examination has shown it to be a variety.

In some internal casts the muscular impressions appear to have been strong, and the shell has been coated inside with rhomboidal crystals of carbonate of lime, which give it a decussated appearance.

Loc. Plymouth, Newton Bushell. Figs. 12, 13. Atrypaplebeia. Transversely obovate, with a produced front, smooth, not

very convex; front slightly elevated, without a depression in the lower valve; beak but little prominent.

This is a common species and varies in form j it was formerly (see Ency. Metrop. loc. cit.) considered to be the young of A. glabra (M. C.269. f. 1.), but the regular convexity of the lower valve and small beaks distinguish it.

Loc. Mount Wise, Plymouth. • Fig- 14. Atrypa triloba. Tetrahedral, with rounded angles, 3-lobed, plaited ; upper

valve extremely gibbous; lower nearly flat; front much elevated, with about 12

E X P L A N A T I O N OF T H E PLATES AND WOOD-CUTS.

plaits, its sides smooth ; lateral lobes reflexed, obscurely plaited. Length and width nearly equal, the depth rather less.

Somewhat resembling the most extravagant but small varieties of A. Pugnus (M. C. t. 497.); but it is more triangular, the plaits are rounder, less elevated, con-tinued almost to the beak, and more numerous ; it is more like T. flexistria (Ph. loc. cit. PI. XII. f. S3, 34.).

A handsome shell. Loc. Plymouth.

Fig. 15. Atrypa Pugnus (M. C. t. 497.). A flattened variety of this very variable species. See also Fig. 18.

Loc. Plymouth. Fig. 16. Atrypa protracta. Triangular, longer than wide, lateral angles rounded;

beak produced acute; sides flattened, front elevated with about 4 plaits, its sides smooth.

Loc. Plymouth. Fig. 17. Atrypa crenulata. Pentagonal, compressed, smooth ; front broadly and sud-

denly elevated, crenulated by numerous small plaits near its margin; sides smooth ; beak scarcely any. A neat species.

Fig. 18. Atrypa Pugnus (M. C. t. 497.). Another variety of the mountain-limestone shell, rather narrower than usual; other varieties also occur here.

Loc. Mount Wise. Figs. 19 and 20. Atrypa desquamata. Oblong, with a straight front, gibbous, deeply

striated; striae increasing in number towards the margin; front obtuse, gently and broadly raised at the edge without elevating the surface; shell longer than wide; upper valve deeper than the one with the projecting beak.

This shell, which is very abundant in the Plymouth limestone, varies exceedingly in size, coarseness of striae, and convexity. In some young individuals the form is nearly globose, while in others it is compressed and lenticular.

Loc. Plymouth. Jftgs. 21 and 22. Atrypa desquamata var. compressa. Suborbicular, compressed; sides

nearly rectangular ; margin nearly even ; valves equal. This differs from the first variety in being flatter and broader; the. upper valve,

not being very convex, does not hang over the beak of the lower so much as in the more convex variety (Fig. 20.), wherefore this seems to have a more projecting beak, which, when broken, appears to have a flat area.

Both the varieties approach so near to A. qffinis (M. C. t. 324.), and more espe-cially to the Eifel specimens of that species, that, were it not for the total absence Of concentric scales, the much more even margin, and the oval not triangular con-tour, we should continue to refer them to the same species. One of the varieties was formerly called T. qffinis (in the EriC'yc. Metrop. loc. cit.).

Fig. 23. This is evidently a young shell; we cannot distinguish it from some specimens of A. aspera (Silur. Syst. PI. XII. f. 5.), but most probably it is a young individual of the A. desquamata.

Loc. Plymouth.

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E X P L A N A T I O N OF T H E P L A T E S A N D WOOD-CUTS.

Fig. 24. Atrypa cuboides. Subglobose, striated; front raised, very flat, with a deep square sinus in the margin, edges sharp, projecting; striae numerous, shallow, about 15 are elevated; beak small, acute; lower valve small, nearly flat, with a large projecting square appendage filling the sinus in the upper one ; striae nume-rous, shallow, extending to the beaks, those on the side much curved.

The parallel striae on the front are a striking character. Loc. Plymouth, also in the Eifel.

Fig. 25. Atrypa latissima. Transversely elongated, smooth, convex, with rather pointed dependent sides ; front elevated, broad, rounded and furrowed, furrows shallow, many very obscure on the sides.

Nearly related to A. platyloba (M. C. t. 406, f. 5, 6.), but the front is rounder, and the furrows much less distinct.

Loc. Plymouth.

P L A T E LVII .

Fig. 1. Atrypa squamosa. Lenticular, ribbed, squamose. The ribs are thick, sometimes forked, and are crossed by concentric thin la-

minae ; they vary in number, and are sometimes so numerous that it is difficult to draw a line of demarcation between this species and T. aspera of Schlotheim, which again passes into A. affinis (Silur. Syst. PI. VI . f. 5. M. C. t. 324>.).

Loc. Plymouth. This shell appears to characterize a stratum of limestone in the Eifel.

Fig. 2. Atrypa impleta. Transversely elongated, ventricose, furrowed; sides rounded ; front elevated with six furrows ; beaks slightly prominent, much wider than long.

The furrows on the surface are shallow and extend to the beaks, the ribs be-tween them are rounded.

Loc. Plymouth. Fig. 3. Atrypa sphcerica. Spherical or rather obovate, transverse, ventricose, plaited;

edge of the front deeply sinuated, with five elevated ribs; beak small, adpressed. Rather wider than long. Loc. Plymouth.

Fig. 4. Atrypa implexa. Obovate, transverse, plaited. Front straight, flat; margin of the front and sides broad; the toothed edges of the valves deeply locked into each other ; plaits numerous, acute.

At first sight this may be taken for Atrypa Wilsoni (M. C ) , but it is not so cy-lindrical, neither is the front so deeply sinuated.

Loc. Plymouth and the Eifel. Figs. 5 and 6. Atrypa primipilaris, Schloth. (Von Buch. Terebr. 68, T. II . p. 29.

Spirifer pentagonus, Sower. See Encyc. Metrop. loc. cit.) Pentagonal, convex, plaited ; front elevated, with three or more plaits^ margin flattened ; a deep angu-lar furrow runs along the middle of the lower valve, bounded by two angular ridges ; beak prominent. Fig. 6 represents a young shell.

Loc. Plymouth, Eifel. Fig. 7. Spirifera (?) crenistria, Phill. (Geol. of Yorksh., 216, PI. IX. f. 6. Sp. reticu-

E X P L A N A T I O N O F T H E P L A T E S AND WOOD-CUTS.

lata, Sowerby. See Encycl. Metrop., loc. cit.) This shell is not very uncommon in the mountain-limestone of the north of England and of Ireland; it also occurs at Matlock. The Irish specimens are often large, with deflected margins, which, with other circumstances, induce us to believe this shell will prove to be a Leptcena.

LoC. Plymouth. Fig. 8. Spirifera nuda. Semicircular, with prominent beaks, smooth, the middle ele-

vated, with a furrow on each side of it; edge obtuse. Loc. Plymouth.

Fig. 9. Spirifera pulchella. Hemispherical, convex, smooth, with three large rounded ribs ; edge sinuated ; beak of the lower valve large, incurved.

This resembles Sp. crispa (Silur. Syst., PI. XII. f. 8.), but is smooth and has fewer ribs.

Loc. Plymouth. Fig. 10. Spirifera subconica, var. (Anomites subconicus, Mart. Pet. Derb. PI. XLV.

f. 6.) This is smaller and has a more curved beak than Martin's shell, but we think it is the same species.

Loc. Plymouth. Fig, 11. Spirifera affinis. Lenticular, ribbed* ribs numerous, branched and crossed

by concentric thin laminae ; hinge-line shorter than the width of the shell; beak of the lower valve prominent, with a triangular flat area.

The prominent beak and large triangular area distinguish this from Atrypa as-pera, Schloth. (Silur. Syst., PI. XII . f. 5.) which it much resembles; it is a re-markable shell.

Loc. Plymouth. Fig. 12. Orthis tenuistriata. Semicircular, with the front straight, striated ; one valve

regularly convex, the other flatter; hinge-area parallel, narrow.

The fineness of the striae and the regular convexity, joined with the parallel area, at once distinguish this and make us doubtful whether it be not a Leptcena; traces of spines are indistinctly visible.

Loc. Morebath. Fig. 13. Pileopsis vetusta (M. C. t. 607). The specimen figured is more involute and

even than the shell in Min. Conch., but examples pretty frequently occur much more like that figure at Mount Wise, &c.

Loc. Plymouth. Fig. 14. Nerita deformis. Subhemispherical, obliquely flattened; whorls rapidly in-

creasing, finely striated ; inner lip uneven, aperture ovate.

This was formerly published (see Encyc. Metrop., loc. cit.) under the name of N. spirata (M. C. t. 463, f. 1, 2.); but it is not so transverse or ventricose, and the spire, though imperfect, could not have been so depressed.

Loc. Stonehouse Hill. Fig. 15. Nerita speciosa. Conical, depressed, smooth?; whorl$ rapidly increasing,

the upper ones very convex, the lower rather square, with a central spiral depres-sion above, concave beneath; aperture subtrapezoidal ? Height and diameter about equal, often 3 inches.

3

E X P L A N A T I O N OF T H E P L A T E S AND WOOD-CUTSL

This fine shell was published (see Encyc. Metrop., loc. cit.) as a var. of N. spi-rata; but the size of the spire, the square form of the lower whorls, and its great size, entitle it to the rank of a species.

Loc. Mount Wise, Plymouth, where it occurs of all sizes. Fig. 16. Pleurotomaria impendens. Conical, short, spirally striated, base concave;

whorls rather flat above,—the lower overhung by the angular base of the pre-ceding whorl; the stria? which encircle the whorls are less distinct towards the upper margin.

The imperfect specimens we possess of this shell will not allow us to draw up a full description.

Loc. Plymouth. Fig. 17. Pleurotomaria cirriformis? (M. C. t. 171, f. 2. Euomphalus delphinuloides ?

Auct.) An imperfect water-worn cast is all we possess of this shell; the true P. cirriformis is found at Paffrath, and has the above name applied to it by conti-nental authors.

Loc. Plymouth, also in the mountain-limestone. Fig. 18. Turbo subangulatus. Conical, elongated; whorls about six, convex, marked

with three obscure spiral ridges on each; aperture nearly circular. This which occurs with the last is in the same bad state of preservation. Loc. Plymouth.

Figs. 19 and 20. Turbo cirriformis, Sower, (see Encyc. Metrop., loc. cit.) Conical, short, oblique, smooth; apex obtuse ; whorls slightly rounded, most prominent below; aperture circular. Height and diameter equal, about £ an inch.

An obscure, yet neat species, common at Stonehouse Hill. Fig. 21. Murex Harpula (M. C. t. 578, f. 5.). Young individuals of this pretty species

are frequent in the Plymouth limestone. Loc. Stonehouse Hill, also Bradley.

Fig. 22. TerebraHennahii, (Ter.Hennahiana, Sower., see Encyc. Metrop. foe. cit.). Sub-ulate, longitudinally and very finely seriated, whorls slightly convex, striae gently bent twice. Diameter not much above £ of the height, which is but fths of an inch.

Very like T.nexilis of the Petherwin beds (PI. LIV. f. 17), but with still finer and less bent stria?, so that Rissoa Lefebvrei, T. nexilis, and the present species will form a neat series of species characteristic of these beds.

Loc. Stonehouse Hill. Fig. 23. Buccinum acutum (M. C. t. 566, f. 1.). This is very imperfect, but cannot be

distinguished from the shell figured in Min. Conch., which is found in Queen's County, Ireland.

Loc. Stonehouse Hill. Fig. 23 a. Buccinum imbricatum (M. C. t. 566, f. 2.). Imperfect specimens, common

in this locality. Loc. Stonehouse Hill, also Bradley, near Newton Bushel.

Figs. 24> to 27. Buccinum spinosum (M. C. t. 566, f. 4.). These specimens are variously distorted, but are all evidently referrible to this species, which we have seen also

E X P L A N A T I O N O F T H E P L A T E S AND WOOD-CUTS.

from the Eifel, and we may remark, that this locality presents the most complete analogy with the Devonian beds.

Loc. Plymouth and Bradley, frequent. Fig. 28. Orthoceras cylindraceum ? An imperfect specimen. We have called it the

same as that in the black limestone of N. Devon (PI. LII . f. 6, 7), though the smooth species are so much alike that without good specimens we would not pre-tend to determine positively any one.

Loc. Newton Bushel, with Brontes Jlabellifer, Goldf. Fig; 29. Orthoceras Tubicinetta. Slowly tapering, ornamented with prominent trans-

verse oblique rings, which are crossed by numerous thread-like ribs without inter-mediate ones, giving it exactly the aspect of the recent Tubieinella Balceharum; section circular.

This very pretty species bears a good deal of resemblance to O. striatulum (PI. LIV. f. 20,) but the longitudinal ribs are much thicker and more prominent than in that species ; it resembles too the O. rugosum, Flem. (Phill. 7. c , PI. XXI . f. 16.), but in that beautiful shell the rings are more distant, and the longitudinal ribs are elevated into spines at short intervals.

Loc. Plymouth. Fig. 30. Remains of an Asaphus or Trinucleust common at Newton Bushel.

It is remarkable that no trace of the position of the eyes remains on the cast, which is also the case with the genus Trinucleus, Murchison.

Fig. 31. Pelvis of Cupressocrinites ? We have seen two specimens of the pelvis in the Plymouth limestone, and one of the arm of this curious animal from Collump-ton, where also large specimens of Brontes flabellifer occur.

Loc. Plymouth, Collumpton,

. PLATE LVIII.

Corals from the limestones south of Dartmoor, described by Mr. Lonsdale. The specimens are principally in the cabinets of Mr. Austen, Mr. Daniel Sharpe, the Rev. R. Hennah, and the Woodwardian Museum, Cambridge.

Fig. 1, 1 a. Astrea pentagona (De Blairiville, Man. d'Actinologie, p. 375.). Cyathophyllum pentagonum (Goldfuss, Petref. p . 60, Tab. 19, f. 3.). Stars irregular in size and shape, but well defined, both on the weathered sur-

face (Fig. 1.) and in a polished section (Fig. 1 a.), the boundaries being formed by zig-zag lines connecting the ends of the rays. On a weathered surface, the centre of the star presents a radiated boss ; but in a polished section it consists of car-bonate of lime, into which the longer rays project more or less, according to the state of preservation. Rays numerous, equal in breadth and uniform in character, but alternately long and short, the termination of the latter assisting to define the centre of the star. From the irregularity in the shape of the star, the length of the rays varies considerably. Character of the perfect terminal star not known.

Loc. Newton Bushel, Torquay, Plymouth. Fig. 2. Stromatopora polymorpha (Goldf. Petref. Tab. 64, f. 8.). Form irregular,

mammillated or branched ; composed of concentric layers, united at irregular di-

E X P L A N A T I O N OF T H E P L A T E S AND WOOD-CUTS;

stances by vertical filaments. The horizontal section (Fig. 2.) presents more or less perfectly, perforated centres, from which irregular tubes diverge, also the terminations of the filaments, and portions of the concentric layers.

Loc. Appleway and near Teignmouth. Fig. 3, 3 b. Astrea Hennahii (Sp. n.).

Stars not defined either on a weathered surface (Fig. 3.) or in a polished section (Fig. 3 a.). On the former, the centre of the star presents a radiated boss, in the latter, fine converging lines. Rays about thirty-six, unequal in length and breadth, and of a crenulated structure. The rays of one star unite with those of the ad-joining stars, the junctions being more or less regular according to their position with respect to the angles of the stars. The rays are alternately long and short, the latter terminating around the central portion of the star, and the former which swell out at the same boundary suddenly become attenuated beyond it, and are prolonged as fine laminae to a reticulated centre. The vertical section (Fig. 3.) is composed of perpendicular close-set parallel lamellae united by innumerable trans-verse plates (Fig. 3 &.).

Loc. Barton Quarry, Newton, Plymouth. Fig. 4, 4̂ /*. Porites pyriformis, Ehrenberg.

Astreaporosa (Goldfuss, 21, f. 7.) Poritespyriformis (Silur. Syst. PI. XVI. f- 2.). This fossil abounds in the Devonian limestones as well as in the Silurian system;

but specimens of the perfect coral, or in that state in which it is presumed the polype ceased to add to its strong fabric, appear to be very rare. I have seen only a few belonging to Mr. Austen's collection. In the young state, and during the period when additions were made to its vertical dimensions, the coral con-sisted of circular tubes, with a projecting margin, from which twelve rays pro-ceeded and united in the centre; and the interstices between the circular tubes were occupied by smaller polygonal ones, open at the upper end. In the state in which it is supposed the polype ceased to add to the structure of the coral, the fossil (Fig. 4, 4 a. 4 c. 4 d. 4 e.) presents in the place of the circular depressed tubes, a raised boss, the margin of which is a sunken and not a projecting line; and the intervals between the twelve rays of the immature coral are occupied by convex surfaces, separated by fine furrows. These bosses are surrounded at irre-gular distances by polygonal ridges, giving the coral the aspect of a series of stars in close contact (Fig. 4.). The ridges and the whole of the surface, which in the young specimens consist of open tubes, are formed of convex papillae preserving in greater or less perfection the angular form of the tube.

The right half of Fig. 4 c. exhibits the usual character of the coral, except that the projecting margin of the circular tubes is wanting ; the left half of the same spe-cimen presents imperfectly the character of the mature coral. Fig. 4 d. has been drawn from a partly polished specimen, the remainder giving examples of the radi-ated boss, but without the bounding polygonal ridges. Fig. 4 /1 is a magnified representation of the polished surface, and Fig. 4 e. of the bosses. Fig. 4 exhibits the character of the perfect coral, and Fig. 4 a. is a magnified portion of the same specimen. Fig. 4 #. displays the internal structure of the fossil.

E X P L A N A T I O N OF T H E P L A T E S AND WOOD-CUTS.

From the above characters, believed to be new among lamelliferous corals, it is inferred that this fossil does not belong to the genus Porites; but it has been thought advisable not to propose, at present, a new one for it.

Loc. Newton Bushel, Marychurch, Plymouth, &c. Figs. 5 to 5 d. Coscinopora placenta t (Goldfuss, PI. IX. f. 18.).

Prof. Goldfuss described the fossil which he has called Coscinopora placenta from apparently a single and probably an imperfect specimen, and was therefore unable to detail fully its characters. It is with considerable hesitation that the Devonian fossil has been assigned to the same genus and species ; but it lias been thought better to do so provisionally than to propose a new generic appellation.

The coral represented in Figs.5to 5d. consists of amorphous masses, composed of very thin concentric layers, traversed horizontally and obliquely by irregular vermi-form cavities, and perforated vertically by cylindrical tubes, which penetrate the whole depth of the specimen, and are bounded by a white circle forming the sub-stance of the tube (Figs. 5, 5 a. 5 b. 5 d.). The distance between the layers is about equal to their thickness ; and the layers are united by vertical filaments of variable form and dimensions, the interstices having a punctured appearance (Fig. 5 a . ) . In some specimens the vertical section is banded, being crossed by stripes of a darker colour (Fig. 5 a.).

This fossil varies greatly in character, according to its state of preservation or mineralization. In some specimens, all structure has nearly disappeared, except the vertical tubes, and the coral then agrees with Goldfuss's description ( C dis-coidea, ports orbiculatis cequalibus, interstitiis lesvibus). Other specimens might be mistaken for masses of Stromatopora concentrica, except that the tubes with careful search may always be found (Figs. 5 b. 5 c. 5 d.) j and the resemblance is still stronger in some masses consisting of gray carbonate of lime, traversed at distant intervals by concentric bands of the decomposed coral.

Loc. Newton Bushel, Torquay, Appleway, Plymouth, &c. PETRAIA (Munster, MS.).

Fig. 6. Petraia Celtica.

Turbinolia Celtica (Lamouroux, Expos. Method. PI. LVIII . f. 7, 8.). (See ante, p. 697.)

Turbinated; external cast smooth ?; internal cast composed of thick lamellae, with two indistinct rows of papillae and a furrow down the middle.

An abundant coral in the slate rocks of Cornwall, but it rarely presents more than flattened casts of the interior. It is placed in this genus because it agrees generically with specimens labelled Petraia from the continental collection of Count Munster.

LoCr Dinas Cove Padstow, Berry Pomeroy, and Fowey. A large coral differing from the above, principally in size, occurs in slate rocks

at New Quay, an4 near Newton Bushel. Fig. 7. Strombodes vermicularis.

Cyathophyllum vermicular e?. (Goldfuss, Petref. Tab. 17, f. 4.). Cylindrical, straight or curved, externally traversed by vertical ridges, marking

E X P L A N A T I O N OF T H E P L A T E S AND W O O D C U T S .

the position of the internal lamellae, and by concentric rugae and fine lines (Fig. 7.). Internally formed of numerous lamellae, which are spirally contorted in the centre, and bifurcate as they radiate more or less regularly to the circumference (Fig. 7 a.). No central cavity crossed by chamber-like septae, that part of the coral being occu-pied through its whole height by the spiral lamellae (Fig. 7 a.).

Loc. Plymouth and Newton Bushel, abundant. Figs. 8 to 8 d. Cyathophyllum cesspitosum (Goldfuss, Tab. 19, f. 2.).

An abundant coral in the Devonian limestones, but seldom well preserved; the exterior portions having been in general removed by atmospheric action. Fig. 8 a. represents a common weathered specimen; 8 c. a section of a similar branch; 8 b. a section of one in which the exterior has been less effectually removed. Fig. 8 represents a specimen of hard limestone, in which the matrix has preserved the exterior portions of the coral. Fig. 8 d. is a vertical section, exhibiting transverse chamber-like plates, and part of another branch or individual, which had sprung from a gemmule deposited on the side of the main coral, and not originated in the subdivision of the older animal. The sections, Figures 8 b. 8 c. and 8 d. in the ab-sence of the central style, sufficiently distinguish this coral from one of similar ex-ternal form, abundant in the mountain-limestone.

Loc. Newton Bushel, Plymouth, Torquay, &c. Fig. 9. Scyphia turbinata (Goldfuss, Petref. PI. II . f. 13.).

Two pyritous specimens imbedded in slate, from the vicinity of Plymouth, are in the cabinet of the Rev. R. Hennah.

Fig. 10. Fenestella antiqua ? (Silur. Syst. PI. XV. f. 15, 18.). Gorgonia antiqua (Goldfuss, Petref. PI. XXXVI. f. 19.). This is also an abundant coral in the slate rocks of the Devonian system; but the

essential characters are seldom preserved. It presents generally a more or less deli-cate net-work (Fig. 10) or cast of the interior surface of the coral; and occasionally impressions of the bifurcated lamellae of the exterior surface (10 a.). Casts of the pores have been also observed in a few instances, and their arrangement led to the belief, when first noticed, that the coral belonged to a new, well-distinguished species of Fenestella. Instead of being arranged in two rows, separated by a ridge or projecting angle, as in Fenestella antiqua (Silur. Syst. PI. XV. Fig. 16. Goldf. PI. XXXVI. f. 9.), the pores or their casts are in contact and disposed alternately, so that the projectin