the dinosaur quarry. dinosaur n - john m. good

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The Project Gutenberg EBook of Dinosaur

National Monument, Colorado-Utah, by

John M. Good and Theodore E. White and

Gilbert F. Stucker

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Title: Dinosaur National Monument,

Colorado-Utah

The Dinosaur Quarry


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uthor: John M. Good

Theodore E. White

Gilbert F. Stucker

Release Date: June 26, 2015 [EBook#49288]

Language: EN

*** START OF THIS PROJECT GUTENBERG

EBOOK DINOSAUR NATIONAL MONUMENT ***

Produced by Stephen Hutcheson, Dave

organ and the Online

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UNITED STATES DEPARTMENT OFTHE INTERIOR

Fred A. Seaton, Secretary


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NATIONAL PARK SERVICEConrad L. Wirth, Director

For sale by the Superintendent of Documents,

U. S. Government Printing Office

Washington 25, D. C. Price 25 cents

THE DINOSAUR

QUARRYDINOSAUR NATIONAL

MONUMENT


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Colorado · Utah

By John M. Good,Theodore E. White

and Gilbert F. Stucker


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NATIONAL PARK SERVICE· Washington, D. C.,

1958

The National Park System, of which Dinosaur National

Monument is a unit, is dedicated

to conserving the scenic,

scientific, and historic heritage of

the United States for the benefit

and enjoyment of its people.


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Contents

Pag

THE QUARRY

THE DINOSAURS First Discoveries

Position of Dinosaurs AmonReptiles

Geologic History What They Looked Like Temperature Tolerance 1

Gizzard Stones 1THE CLIMATE, LIFE, ANDLANDSCAPE OF JURASSIC TIME 1

How Do We Know? 1

ANIMALS FROM THE QUARRY 1


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Why So Many? 1How Were They Preserved? 2

How Were They Exposed? 2

WHY DID DINOSAURS BECOMEEXTINCT? 2

HISTORY AND DEVELOPMENT OFTHE QUARRY 2

Discovery and Early Years 2Starting the Quarry 2

Extent and Development of the Fin

2Work Methods 3

Further Development 3Protecting the Quarry 3

Present Development 3THE SCENE TODAY 3

KEY TO PRONUNCIATION 4SUGGESTED READINGS 4


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JURASSIC LANDSCAPE SHOWING

ANIMALS AND PLANTS THAT LIVEDHERE DURING MORRISON TIME.

(FROM A PAINTING BY ERNEST

UNTERMAN.)


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As you approach Dinosaur Nationa

Monument from Jensen, Utah, you sehe mass of Split Mountain and the deepshort canyons that scar its south slopnear the Green River’s gorge. As yo

cross the National Monument boundarhe grand view is lost and you begin t

notice details. The masses of gray shalhat seem to be carelessly piled agains


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he tilted sandstone layers are bare ovegetation. The ground between the hilland the Green River is covered wit

sagebrush and greasewood, while alonhe river itself are a few larg

cottonwood trees and many bushes. Asharp turn brings a change of scene aour car enters a portal in the wall yo

have been following. The pronounceilt of the rocks becomes more obvious.

A final steep climb and the visitor centes at hand. This building encloses

significant part of the Dinosaur Quarry

perhaps the greatest deposit of fossidinosaur bones known today. From thiquarry have come many of the dinosauskeletons that are seen today in our grea


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museums. After parking, a short walk the overlook on the southeast reveals

splendid view of Split Mountain

Between that broad arch of erodesandstone and the quarry lie steeplilted sedimentary rocks of variou

compositions and hues. Buff and grasandstones that weather into soft shapeare separated by reddish-brown shaleDirectly to the east is a section o

varicolored shale whose pastel pinksreds, greens, grays, and whites justifhe name of “rainbow beds” that wa

given them by geologists. In the uppe

part of this section are hard sandstonand limestone layers that resist therosive action of wind and water. Thestand higher than the softer shales an


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form hogbacks that rim Split Mountain.

One of these layers can be traced acros

he ravine immediately east of thparking area into the sandstone ledghat forms the north wall of the visito

center. This is the famous Dinosau

Ledge.


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The Quarry

The Dinosaur Ledge is famous becaushere the world’s greatest store of fossibones of these long extinct reptiles habeen uncovered. Two groups, or orders

of dinosaurs have been discovered, wita number of different types or kindsomewhat related to each other withihese orders. From the fossil bones

scientists can tell that these creaturevaried greatly in size and habits oiving.


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TILTED ROCK STRATA NEAR THEDINOSAUR QUARRY.

Some were the size of chickens, otheras big as horses, and others of sucgigantic size that no land animal alivoday can compare with them. Som

were flesh-eaters as indicated by th


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size and shape of their teeth and theiong sharp claws. Others were plant

eaters and again it is the structure o

heir teeth and feet that tell us this. Thflesh-eaters were two-footed anwalked on their hind legs, balancinhemselves with heavy long tails. Thei

short front legs were used as clawedarms for tearing at the flesh of othedinosaurs. Many plant-eaters, on th

contrary, were large, heavy, four-footebeasts, often with long necks and tailsMany of the dinosaurs were landwellers, and many others lived in th

great marshes and swamps of the lonMesozoic (middle life) Era of the earth’

history.


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Though the subclass of reptiles we caldinosaurs lived all through the MesozoiEra, those whose fossil bones have bee

uncovered in this Dinosaur Quarry arembedded in a stratum of rock called thMorrison formation. This rock stratudates from the Jurassic Period in thmiddle of the Mesozoic Era.


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The Dinosaurs

FIRST DISCOVERIES

Today, most of us would recognize fossil bone for what it is, but in th1790’s things were different. Isolateegbones, vertebrae, and teeth of hug

reptiles had been dug out of certaisedimentary rocks of Europe and NortAmerica but their scientific importancwas little understood.


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These specimens were found by peopln all walks of life and it was naturahat their curiosity was greatly aroused

The finders took the specimens tsomeone nearby whom they consideremore competent to tell them somethinabout these strange bones and teeth. Inearly all cases these “experts” werdoctors of medicine. They studied thfossil specimens and reported on them a

regular meetings of the learned societieof which they were members. It wacustomary to put the fossils in thcollections of these societies where the

could be studied by other members. Iorth America most reports of thes

early discoveries are found in throceedings of the America


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hilosophical Society in PhiladelphiaPa.

By 1842 accumulated knowledge ohese large reptiles was sufficient t

show that they were distinct from angroup then known. This was firs

recognized by Sir Richard Owen of thBritish Museum. It was he who namehe group Dinosauria. The name is mad

up of two Greek words: deinoterrible) plus sauras (lizard).

As knowledge of these unusual reptile

ncreased through the discovery oadditional types and more complete anbetter preserved specimens, it becamevident that dinosaurs were neither


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single group of reptiles nor were all ohem large. Actually the dinosaurs show

as much diversity in size, body form, an

habits as any group of reptiles. Thsmallest dinosaur walked on its 2 hinegs like a chicken and was about th

same size. The largest walked on all egs, was about 80 feet long, an

weighed 30 to 40 tons. As examples ovariety in body form there are the two

footed, flesh-eating Antrodemus, tharmored Stegosaurus, the turtle-lik

nkylosaurus, the horned Triceratopshe huge Apatosaurus, the two-foote

vegetarian Camptosaurus, and the greavariety of head forms in the aquatihadrosaurs. Although there were twdistinct groups, we still retain the ter


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“dinosaur” as a convenient name for alof them but qualify it by saying, flesheating dinosaur, plant-eating dinosaur

armored dinosaur, etc., to indicate thparticular type we are talking abouPerhaps you are wondering how alhese ancient creatures are related t

reptiles in general. Where do they fit ihe classification system devised t

bring order to this mass of knowledge?

POSITION OF

DINOSAURS AMONG

REPTILES


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t seems there are several orders oreptiles similar to and closely related the dinosaurs. Remains of these reptile

are found in the sedimentary rocks whiccontain the earliest known dinosaurs. Anumber of them resembled the dinosaurbut do not quite meet the requirements afar as details of the skeleton arconcerned. In the scheme oclassification these orders of reptiles ar

grouped together into the subclasrchosauria. This subclass includes th

dinosaurs, crocodiles, and the flyinreptiles. The lizards, snakes, turtles, an

he tuatera of New Zealand belong tother subclasses of reptiles which havbeen distinct from that of the dinosauras far back in geologic time as we ca


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race them. The kinship between thdinosaurs and the small lizards living ihe monument today lies only in that bot

are reptiles. The only living relatives ohe dinosaurs are the alligator and th

crocodile.

The dinosaurs were so numerous, and sdominated the whole of the MesozoiEra, that this period of earth history i

frequently referred to as the Age oReptiles.

GEOLOGIC HISTORY

The Mesozoic Era began some 20


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million years ago and ended some 6

million years ago. Although many otheanimals lived during that era, th

dinosaurs were the dominant forms oanimal life on land. The 140 millioears of the Mesozoic are divided int

geologic periods named Triassic (tholdest), Jurassic, and Cretaceous (thmost recent). Continental depositrepresenting each of these periods hav

been found in all parts of the world anon all continents. Dinosaur bones havbeen found in these deposits—even isuch far-away places as Australia an

he southern tip of South America. OnlJurassic dinosaurs have been found aDinosaur National Monument.


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Coelophysis —SMALL TRIASSIC

DINOSAURS, FORERUNNERS OF THEHUGE DINOSAURS OF JURASSIC

PERIOD. (DRAWN BY MARGARET M.

COLBERT. COURTESY, AMERICAN

MUSEUM OF NATURAL HISTORY.)


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The oldest known dinosaurs are found irocks of the Triassic Period. The smalleof these were chicken-size and th

argest were about as big as kangaroosAll of these Triassic dinosaurs werwo-footed. They can be divided int

flesh-eaters and plant-eaters, althougnone are believed to have beeparticularly specialized in their foohabits. In general the flesh-eaters wer

small, agile, and had sharp teeth foseizing and overpowering active preyThe plant-eaters were larger with ratheong front legs and small blunt teet

suited only to cropping vegetationThese plant-eaters are believed to be thTriassic ancestors of the giant marshdwelling dinosaurs of the Jurassic an


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Cretaceous Periods.

A greater variety of dinosaurs live

during the Jurassic Period than in thTriassic. Both two- and four-footeypes were present. The flesh-eater

remained two-footed but increased i

size. Antrodemus, perhaps the besknown, was much bigger than kangaroo. The larger plant-eater

weighed from 30 to 40 tons and all werfour-footed. The largest land animalshey lived on dry land and in the swamphat formed an important part of th

Jurassic landscape. The first of tharmored plant-eating dinosaursStegosaurus, inhabited the dry plainsThere were also some smaller


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kangaroo-size plant-eaters that werwo-footed.

A wide variety of dinosaur fossils habeen found in the rocks of thCretaceous Period, the last of thMesozoic Era. The huge swam

dwellers still thrived. The flesh-eaterhad evolved much larger types anncluded 40-foot Tyrannosaurus, th

argest that ever lived. All the flesheaters walked on their hind legs as diheir predecessors of the Jurassic an

Triassic Periods.

ew and interesting dinosaurs werpresent among the flesh-eaters. Horneforms, somewhat similar to th


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rhinoceros but much larger, wercommon. Also common were the turtleike ankylosaurs. Perhaps the oddest an

most interesting dinosaurs of thCretaceous were the two-footehadrosaurs. These excellent swimmerhad weird head shapes with complicateskull passages and openings. They wera very successful group and at least 1different kinds are known from th

Cretaceous rocks of North America.

WHAT THEY LOOKEDLIKE

deas about the external appearances o


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dinosaurs have been developed aftemany years of work and study. They ara combination of the ideas of severa

people who had studied differenspecimens of a single species. Let ureview briefly the materials and wornecessary to arrive at a reasonablaccurate picture of the body form anexternal appearance of these strangreptiles.

The first requirement for arriving at good idea of the build and physicaattitude of an animal is a nearly entir

skeleton. We cannot have too much of thanimal’s skeleton missing or we mamake a serious error. But if the left hineg is missing and we have the right, w


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are not seriously handicappedHowever, if both hind legs are missinwe must restore them according to

similar animal whose hind legs arknown.

After the nearly entire skeleton has bee

found it must be collected with greacare. This is a rather involved procesand, for some of the large dinosaurs,

or 3 months work may be required. Thspecimen is first uncovered and thfossil bone is treated with a preservativsuch as gum arabic, shellac, or one o

he plastics. An accurate diagram of thspecimen as it lies in the rock is madon cross-ruled paper. A trench 2 or feet wide is then dug around th


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specimen. The depth of the trench idetermined by the width of the specimeand the nature of the rock.


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PUTTING PLASTER CAST ON A FOSSILBEFORE REMOVING IT FROM THE

QUARRY.

f the specimen is too large to take out ione piece, as most dinosaurs are, it idivided into sections which ar

numbered serially as they are taken out


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Each section is bandaged in strips oburlap dipped in plaster of Paris. Aftehe plaster has set, the section is turne

over and the bottom is sealed witburlap and plaster. The section iabeled with the appropriate number anhe section and number are shown on th

diagram.

When all of the sections have bee

bandaged and numbered they are packen strong wooden boxes and shipped the laboratory.

The work in the laboratory is mornvolved than that in the field, an

extreme care must be exercised to bsure that the bones will be undamaged


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n most cases the bones have beebroken by natural causes as they lay ihe rock before discovery. All the piece

of each bone must be thoroughly cleaneand securely cemented together. This is very time-consuming task and for a largdinosaur like Apatosaurus it requires men 4 or 5 years to complete the task.

After all of the bones are cleaned an

cemented together the vertebral colums laid out in its proper sequence on sand table. Special care is exercised tbe sure that the vertebrae fit correctl

with each other. In this way the correccurvature of the vertebral column idetermined. The proper relationships ohe hip bones and ribs to the vertebrae


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he shoulder blade to the ribs, anelements of the limb bones to each otheare determined in the same manner. Al

of this work is necessary to correctlfashion the steel framework which wilsupport the skeleton when it is placed oexhibition. The results of this carefuwork must be the framework of aanimal which could, if living, easily ghrough the normal activities of life suc

as securing food and escaping enemies.

ow that the framework of an animahas been set up so that it could mov

about if it had muscles, skin, and lifehow do we know how large the musclewere and where they were placed? It inecessary to have a thorough knowledg


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of the muscles of a recent animal similao the one we are restoring so that w

will know what we are looking for in th

fossil. The areas at which muscles arattached to bones are called musclscars and are identified by their rougsurfaces. Often the necessarnformation can be obtained fro

publications which usually represent thwork done by graduate students fo

advanced degrees. At other times wmust make our own investigation. Thus iwe know what muscle we are lookinfor and the size and shape of its muscl

scar, we can determine whether thmuscle is a spindle-shaped mass or broad sheet.


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After we have determined the size anposition of the muscles which operathe limbs, head, and neck, we have

reasonably accurate idea of the externaform of the animal, but we still knownothing of the nature of the skin whiccovered the body. Since dinosaurs werreptiles, we are obliged to assume thahey were covered with a scaly skin i

order to preserve the body moisture

one of the modern reptiles possessweat glands in the skin. If they did nopossess a waterproof covering of scalehey would die in a few hours as a resu

of the loss of body moisture bevaporation through the skin. It ipossible that some of the marsh dwellerike Apatosaurus had naked skin whic


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was, as in the elephant, nearly an inchick. The elephant does not posses

sweat glands but the outer half of its ski

s composed entirely of dead cellwhich form a covering as waterproof ahe scales of today’s reptiles.

There have been only a few lucky findof mummified dinosaurs which show thmpressions of the scales. We know tha

all lizards do not possess the same typof scales, and therefore, by analogy, wcannot assume that the dinosaurs didEventually, we will probably find tha

he dinosaurs exhibited as great a varietof scale-types as do today’s lizards. Aet we have found nothing in the fossi

record which indicates the color of th


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dinosaurs. Again, we can only assumhat they exhibited as great a variety o

colors as do our lizards. So also, w

assume their body functions wersomewhat similar to the reptiles another related animals we know today.


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DINOSAUR FOSSIL WITH SKIN AND


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LIGAMENTS PRESERVED. (NOT FROM

DINOSAUR QUARRY. COURTESY,

AMERICAN MUSEUM OF NATURAL

HISTORY.)


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RARE FOSSIL OF DINOSAUR SKIN.(COURTESY, AMERICAN MUSEUM OF

NATURAL HISTORY.)


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TEMPERATURE

TOLERANCE

We know the body temperatures oreptiles vary with that of the air or waten which they live, as they have n

means of internal temperature controThey are very sluggish when their bodemperatures are low and become mor

active as these temperatures rise, buonly to a certain point. If the bodemperatures of reptiles become to

high, they die in a few minutes.

A group of physiologists from ColumbiUniversity spent nearly 2 months isouthern Florida experimenting o

reptiles. They determined the rate of ris


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of body temperatures of large lizardand alligators of all sizes durinexposure to the midday sun. As wa

expected, the smaller the reptile thmore rapid the rise in body temperatureDinosaurs were reptiles so we can makwo assumptions: That their physiolog

was very similar to that of livinreptiles; and that the rate of rise of theibody temperatures from exposure to th

sun would follow the principles founfor living reptiles.

By applying these principles to th

dinosaurs, this group of scientistcalculated that if the great bulk of a

patosaurus were exposed to the direcrays of the sun at an air temperature o


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110° F. for 36 to 40 hours, its bodemperature would rise only 1° F

Therefore, if these calculations ar

correct, it is probable that the very sizof the huge dinosaurs operated tmaintain a fairly constant bodemperature. Consequently, daily an

seasonal temperature changes probabldid not affect the activities of the largdinosaurs. However, the activities of th

small ones may have been affected bhe daily range in temperature.

GIZZARD STONES

For many years rounded stones with


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very high polish have been found in thsedimentary rocks which contain boneof extinct reptiles. The polish on thes

stones is very much higher than coulhave been applied by the action of wateor wind. Some look as though they habeen polished by a jeweler. Since wcannot attribute this very high polish twind or water action, we must see

another agent.


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Protiguanodon. NOTE GIZZARD STONES

INSIDE RIB BASKET. (COURTESY,

AMERICAN MUSEUM OF NATURAL

HISTORY.)

Just as chickens swallow fine gravel fo

heir gizzards to aid digestion, so it ihought that some large dinosaurswallowed stones for the same purposeThere is some evidence to support thi

dea. Several specimens of a group oswimming reptiles, called plesiosaurswhich swarmed the Jurassic anCretaceous seas, have been found withighly polished stones inside the ribasket. Also a mass of highly polishestones was found similarly associate

with one dinosaur, Protiguanodon, i


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he Lower Cretaceous rocks oMongolia.

On the other hand, no highly polishestones have been found associated withe specimens in the Dinosaur Quarry o

anywhere in the quarry. A search of th

many publications on dinosaurs has nourned up any mention of highly polishe

stones being associated with any of th

many specimens found in NortAmerica. Thus the evidence which whave does not permit us to say that thdinosaurs found in the quarry did or di

not possess gizzard stones.


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The Climate, Life, and

Landscape of Jurassic Time

The geologists who attempt treconstruct the geography and climate ohe Jurassic Period first gather al

possible facts and try to fit them togetheo form a logical pattern. The results arhen examined for weak points and a

attempt is made to find field evidenchrowing light on these weak points. Th

final result represents the sum of ouknowledge at the time but is subject t

change as new facts are obtained. Thu


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he following outline represents presenhinking that may be changed somewha

by future studies.

The land for miles around the DinosauQuarry was a low-lying desert in earlJurassic time. The mountains you se

now had not yet been formed, and thwhole desert area lay close to sea leveGreat restless sand dunes drifted acros

his level land to form a blanket 700 feehick. As the earth’s crust sank, thesdunes were covered by a long arm of aarctic sea that extended southward alon

he present trend of the Rocky Mountainacross Canada, Montana, Wyoming, anUtah. Millions of years later, in latJurassic time, when the Morriso


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formation was deposited, the area rosagain and the stage was set for thdinosaurs.

magine if you can, the vast plainextending from Mexico to Canada anfrom central Utah to the Mississipp

River. To the west were high mountainn the Great Basin region of Nevada an

western Utah. From these highland

flowed great sluggish streams thacarried large amounts of sand and siltSince the plains were almost flatswamps and small lakes were probabl

numerous. The streams may havchanged their courses from time to timas they were not confined to deevalleys. When the whole region emerge


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from the sea the climate became morhumid. Volcanoes were active far to thwest; the winds carried clouds o

ejected dust eastward and depositehem on the plains. Semi-tropica

conditions probably existed throughouhe United States and in parts of Canada

These deposits are called the Morrisoformation.

The warm humid climate provided ideaconditions for plant growth. Greaforests of lush vegetation covered thand. Many of these plants have sinc

disappeared, but some of their relatespecies may be found today in thropics. Most of the plants of ou

Temperate Zone had not yet evolved


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However, there were tall stands of ype of pine, and other evergreens. Ther

were also gingkos and curious tree ferns

Various herb ferns formed a grouncover as thick and lush as grass on well-watered prairie. Palmlike fern

resembling today’s cycads wercommon, while along the river grewhorsetail rushes like those living today

Flowering plants of the Recent Epoch ogeologic time (in which we are nowiving) had not yet made thei

appearance. Thus the hardwood

broadleaf forests of oak, elm, beechmaple, and similar trees were absent. Soo were the flowering shrubs familiao the Temperate Zone. Even the grasse


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were missing.

However, if you could picnic in thi

strange plant world you would soon bslapping mosquitos and cursing the antsFor even in such ancient times thesnsects were present; and so were

great variety of other insects as is knowfrom the more than 1,000 species thahave been discovered in Jurassic rocks

Among them were representatives omost modern orders such agrasshoppers, beetles, moths, ants, anflies. Jurassic insects probably looke

much like those of today.

Among the most interesting of the strangreptiles were the pterosaurs tha


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dominated the skies. They resembled thmodern bats in some ways but theieathery wings were supported on eac

side by one finger instead of four, anheir skins were scaly or bare instead o

hairy. Some forms had long tails thawere flattened at the tip and helped thebalance in flight, but others werailless. Some pterosaurs were no largehan sparrows while others had win

spans of 3 to 4 feet.

Crocodiles sunned themselves on thbanks of sluggish streams and lakes

They probably looked a good deal likhose that live in modern swamps anheir habits were similar. Many a smal

dinosaur fell victim to their stealth


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attack and disappeared beneath thwaters of some ancient stream.

Birds have been found in Upper Jurassirocks of Germany and may have livehere too. Their fossil remains woulprobably have been classed as reptile

had not feather imprints been a part ohem. About the size of crows, thes

reptile-like birds had small conica

eeth, three-clawed fingers on eacwing, and a long tail instead of the fan ofeathers seen on modern birds.

Small mammals were also living at thime the Morrison formation was bein

deposited and their remains have beefound in the dinosaur quarry at Com


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Bluff, Wyo. The largest ones were abouhe size of a house cat but the majorit

were much smaller, probably about th

size of today’s mice.

We do not know much about the habits ohese early mammals but they wer

probably rather shy and retiring. Thiwould be expected in the world of giantwhere they lived. Some of them lived i

rees and there was one group whosskull characteristics resemble those ohe rodents. It is likely that thes

primitive mammals lived a life simila

o that of the rodents millions of yearater.

This, then, was the setting, the stag


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upon which the dinosaurs played theieading roles. Although we hav

restricted our discussion to Morriso

ime in northeastern Utah, the same osimilar animals lived all over the worldWorldwide humid and mild climateproduced a similarity of plant ananimal life during most of the MesozoiEra whose like has not been seen in thast 60 million years. It was a strang

world and ruled by strange animals, but must have been an interesting one.

HOW DO WE KNOW?

This is a good time to stop and try t


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explain that this story, of plants an

animals of the past, has a firm foundation today’s facts—it is not a fantasy.

The methods by which geologists anpaleontologists have established the ageclimate, and life of Morrison time canno

be described for you here in detail. Tattempt such a description would requiroo much space and would probabl

seem dull to most readers. Perhaps thbest approach is to describe somfeatures and explain how they contributo our knowledge.

The rocks that were deposited here iMorrison time tell us much of the storyThe sandstones were once strea


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sandbars or perhaps beaches arounakes. The shale, siltstone, and cla

were muddy stream or lake bottoms. Th

discontinuous ledges of conglomeratprobably represent gravel bars formeduring flood stages or at places wherhe stream currents were very swift.

Just rocks you may say—but looclosely. A piece of sandstone contain

grains of sand that differ from each othen size, shape, and compositionFrequently these characteristics point the source of the sandstone and tel

something about the conditions at thime it was deposited. Chunks of blac

material are examined closely and provo be charcoal—carbonized remains o


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plants.

Microscopic examination of cla

fragments reveals shards of volcaniglass and ash that speak of activvolcanoes. Sometimes these clays beahe carbonized imprints of delicat

plants that long ago sank to the bottom osome lake or stream where they werburied and fossilized.

The fossils themselves are mosmportant in reconstructing conditions ohe past. We find the shells of fresh

water clams in the sandstones witdinosaur bones. Crocodile bones aralso common. We are reasonably surehen, that these deposits of sand and mu


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were formed in rivers and lakes whehe climate was mild.

We reason by analogy. For examplefossil plants and animals havcounterparts or descendants in the worlof today. We assume, in the absence o

contrary evidence, that the fossil animalived like their present-day counterparts

Although no birds, mammals, o

pterosaurs have been found in thiquarry, they were probably living herwith the dinosaurs. It is possible, in facprobable, that some modern animals an

plants live in different environments thadid their Morrison ancestors anrelatives but we have no way oknowing which ones they were. We ca


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only take the data available, arranghem as logically as possible, an

continue the search for more. Some ma

scoff at such methods of reasoning yehey do provide good results. What othe

methods can be used when the worlunder investigation lies millions of yearn the past?


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Animals from the Quarry

n the rocks of the Morrison formation ahe quarry, both orders of dinosaurs ar

found— Saurischia and OrnithischiaPaleontologists have divided th

dinosaurs into these two groups on thbasis of important skeletal differencesThese differences remain constant fohe orders and vary within each orde

only in small details.

The important structural difference idinosaurs is found in the pelvis. In al


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and vertebrates, the pelvis is made upof three pairs of bones called the iliumpubis, and ischium. The paired ilium i

oined to each side of the backbone anprojects downward to meet the pubiand ischium at the socket for the head ohe thigh bone. The pubis forms the fronhird and the ischium the rear third ohis socket. In the order Saurischia th

bones of the pelvis are arranged as i

most reptiles and mammals. In the ordeOrnithischia the pubis extendbackward along the ischium as it does ihe birds.

Two types of saurischian dinosaurs arfound in the quarry. Antrodemus, a flesheating type, was about the size of


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horse, but was two-footed. It had stronsharp claws on its feet. Its teeth werabout 2 inches long, flattened from sid

o side and with fine serrations on fronand back edges. Actually it is not knowwhether Antrodemus overpowered ankilled the large swamp-living dinosaursor merely fed on their carcasses aftehey had died from other causes

However, there has been found in th

quarries at Como, Wyo., a partiaskeleton of Apatosaurus with grooveon the bones which suggest tooth marksThe spacing of these grooves fit th

spacing of the teeth of a specimen ontrodemus found in the same quarry.


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A. ORNITHISCHIAN PELVIS. B.

SAURISCHIAN PELVIS.

KEY: IL—ILLIUM; IS—ISCHIUM; P—

PUBIS.

The plant-eating dinosaurs of the ordeSaurischia which are found in the quarrwere all four-footed. They had bodieabout the size of an elephant or largerThe principal differences between thflesh- and plant-eating dinosaurs wer

he length of the neck and tail, the detail


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of their skull structure, and other parts oheir skeleton.

patosaurus is perhaps the mosfamiliar dinosaur to most of us. Its hinegs were much longer than its front one

and gave the animal a high-hipped

stooped appearance. Apatosaurus waabout 70 feet long and probably weigheclose to 40 tons. Diplodocus was longe

one of them 75½ feet) but was slendeand lightly built. Its neck was longer ant had a whiplash tail that looked mucike the tail of the modern whiptaile

izard. Diplodocus also had long pencilike teeth different from those of an

other known dinosaur. Barosaurus haan extremely long neck with lon


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ndividual neck bones. Two members ohe genus Camarasaurus are similar t

each other except for size; one wa

small, but the other was as large apatosaurus. Camarasaurus had longe

front legs than Apatosaurus and wagenerally better proportioned.


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Antrodemus, THE FEROCIOUS

CARNIVORE OF MORRISON TIME.(FROM A DRAWING BY CHARLES R.

KNIGHT. COURTESY, AMERICAN



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THE GREAT SAURISCHIAN PLANT-

EATER Apatosaurus louisae —ABOUT 70FEET LONG. (FROM A DRAWING BY A.

AVINOFF, CARNEGIE MUSEUM.)

Fossils of the saurischian plant-eaterare found much more frequently thahose of flesh-eaters and are usually i

sedimentary rocks which contain beds o


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clam shells. For this reason it seemprobable that they waded lagoons anstreams, feeding on aquatic and bank

side vegetation. The suggestion has beemade that the larger dinosaurs could noeven walk on dry land because theiweight would have crushed the bones oheir feet; they needed the buoyancy o

water to help support them. Howeverfootprints of a huge dinosaur, muc

arger than any from the quarry, havbeen found near Glenrose, Tex. Tharge footprints were made on a sand

beach of a sea in Lower Cretaceou

ime. Thus we know that they could walon dry land if they wanted to.

All of the dinosaurs of the orde


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Ornithischia were plant-eaters, anwere of both two- and four-footed typesThe two-footed types found in the quarr

are Camptosaurus, Dryosaurus, anaosaurus. These forms had wel

developed front legs, though mucshorter than their hind legs, whicsuggests that they may have droppedown on “all fours” while feeding oresting. The teeth were small, chisel

shaped, and fitted only for croppinvegetation. The larger specimens oCamptosaurus reached a length of 1feet but Laosaurus was only 2½ fee

ong.

Stegosaurus is the only quadrupefour-footed) of this order found in th


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quarry. It had long hind legs and vershort front legs. It reached a length of 1o 20 feet and was 10 to 11 feet hig

over the hips. The most characteristifeature of this form was the double rowof bony plates down the back and thgroup of spikes at the end of the tail. Theeth were similar to those o

Camptosaurus, but much mornumerous.

Only two other groups of reptiles havbeen found in the quarry at Dinosau

ational Monument and their remain

are rare. These are the crocodiles anurtles. Two crocodiles are known; tharger one, Goniopholis, was about th

size of existing alligators and did no


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differ in external appearance fropresent-day crocodiles. The smaller onwas less than a foot long and resemble

a 2 weeks’ old alligator as much aanything. However, we know from thexture of the surface of the bone that

was not a young animal. The turtleGlyptops, was about the same size angeneral appearance as the pond turtles ooday.

WHY SO MANY?

The partial skeletons of more than 2ndividual dinosaurs and the scattere

bones of about 300 more have bee


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discovered in the Dinosaur QuarryMany of the best specimens may be see

oday at museums of natural history i

he larger cities of the United States anCanada. The quarry is easily the largesand best preserved deposit of Jurassidinosaurs known today.

How and why did so many dinosauskeletons accumulate here? How wer

hey preserved? These are among thcommon questions asked of park rangerand naturalists at Dinosaur. The answes a combination of circumstances an

uck.

Many people get the impression from thmass of bones in the quarry wall tha


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some catastrophe such as a volcaniexplosion or a sudden flood killed whole herd of dinosaurs in this area

True enough this could have happenedbut it probably did not. The maireasons for thinking otherwise are thscattered bones and the thickness of thdeposit. In other deposits where thanimals were thought to have dieogether, the skeletons were usuall

complete and often all the bones were iheir proper positions, or articulated. I

a mass killing the bones would havbeen deposited on the stream or lak

bottom together at the same level, but ihis deposit the bones occur throughout

zone of sandstone about 12 feet thickThe mixture of swamp dwellers and dry


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and types also seems to indicate that thdeposit is a mixture derived frodifferent sources. Rounded fragments o

fossil bone have been discovered in thquarry—fragments that attained theipebblelike shape by rolling along thstream bottom.

f the mass of bones was not the result ocatastrophe what did happen? Th

quarry area is a dinosaur graveyard, noa place where they died. A majority ohe remains probably floated down a

eastward flowing river until they wer

stranded on a shallow sandbar. Some ohem, such as the stegosaurs, may hav

come from far-away dryland areas to thwest. Perhaps they drowned trying t


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ford a tributary stream or were washeaway during floods. Some of the swamdwellers may have mired down on th

very sandbar that became their gravwhile others may have floated for milebefore being stranded.

Even today similar events take placeWhen floods come in the spring, sheepcattle, and deer are often trapped b

rising waters and frequently drownTheir bloated carcasses floadownstream until the flood recedes aneaves them stranded on a bar or shor

where they lie, frequently half buried ihe sand, until they decompose. Earlravelers on the Missouri River reportehat shores and bars were frequentl


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ined with the decomposing bodies obison that had perished during sprinfloods.

n Dinosaur National Monument, thpositions in which partial skeletons ohe dinosaurs lie suggest that the

decomposed on a sandbar. The bones ohe underside of a skeleton are ofte

arranged as they were when the anima

was alive, while those on the upper oexposed side may be scattered. Sucscattering would be expected as thigaments and muscles holding the bone

ogether decomposed; stream currentand scavengers could then dispershem. Stream currents are suggested bhe position of the long, flexible tails an


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necks of the large plant feeders. Theseike streaming water plants in a riverrail downstream to the east.


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Camptosaurus —AN ARNITHISCHIANPLANT-EATER. (DRAWN BY J. G.

GERMAN. COURTESY, AMERICAN


HOW WERE THEY


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PRESERVED?

The concentration and burial of dinosaubones is only the beginning of the fossistory. The combination of circumstance

which operated here was a common on

and yet fossil quarries are rare. WhyThe bones have to be preserved and thiseldom happens. The bones that arburied in one flood are frequentl

unearthed and scattered by the nextThose that are exposed to the weatheusually disintegrate completely in a few

ears. The bones in the Dinosaur Quarrdid not.

Sometime after they were buried, th

organic minerals of the bones were mor


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or less completely replaced by mineralof inorganic origin such as silica. None knows exactly why or how thi

happened, but it did. Most geologisthink this replacement process occur

when subsurface or ground watecontaining soluble and colloidaminerals dissolves a molecule of thbone and immediately replaces it with new mineral. Roughly such a process i

ike removing red bricks from a housand substituting yellow. When thsubstitution is complete, the house stilhas the same dimensions but it i

composed of different materials. Threplacement was a faithful one, toobecause microscopic structure of thoriginal bone was faithfully reproduce


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by the replacing minerals.


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ROAD MAP

DINOSAUR NATIONAL MONUMENT

UTAH - COLORADO

High-resolution Map

Following Morrison time, thousands o

feet of younger sediments wer


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deposited on the sandbar that containehe dinosaur bones. The whole sequenc

of sediments was compacted into roc

and some bones were crushed andistorted.

HOW WERE THEY

EXPOSED?

After the sediments became rock and thbones had probably been replaced b

stone (fossilized), this part of the worldwhich lay near or below sea level fomillions of years, began to rise. Greaforces acted upon the earth’s crust

These forces created faults, or fractures


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n the rock crust along which movemenoccurred. And what had once been sebottom was moved upward and becam

ofty mountains. This titanic change habeen called the Laramide Revolution; iclosed the Mesozoic Era with th

formation of the Rocky Mountains.


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Stegosaurus. AN ARMORED DINOSAUR

OF THE JURASSIC PERIOD. (FROM A

DRAWING BY CHARLES R. KNIGHT.

COURTESY, AMERICAN MUSEUM OF

NATURAL HISTORY.)

Although the effects of the LaramidRevolution were not as profound a


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Dinosaur as they were east of it, thewere quite important. The rocks werifted to form the southwest flank of Spl

Mountain—a small arch, or anticline, ohe south side of the Uinta Mountains

This mountain building explains thpronounced southward tilt of thDinosaur Ledge and other rock layervisible in the quarry area. As the lanrose, streams flowed more rapidly

cutting deeper into the rocks ancarrying away the debris. Graduallhousands of feet of this debris—shale

sandstone, and clay—were strippe

away through erosion.

Finally all the material on top of thMorrison sandbar weathered away


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Some 140 million years after burial thfossil bones were exposed by the agenhat had buried them so long ago—

running water! All that remained was fohem to be found, and that was thuckiest chance of all. Just suppose the

had been uncovered a million years ag—only a second in geologic time. None would have been present to discovehem, and through the years they coul

well have crumbled into dust and beeblown away.


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Why Did Dinosaurs Become

Extinct?

At Dinosaur National Monument onlMorrison rocks of the upper JurassiPeriod contain the fossil bones o

dinosaurs. After Morrison time, thCretaceous seas invaded this area. Morhan 5,000 feet of sandstone, shale, an

mudstone were formed from sedimentdeposited in these seas.

Elsewhere in North America and the res

of the world, the diversity and number


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of dinosaurs actually increased. Entirelnew groups evolved and achievesuccess in the battle for survival. Th

climax of reptile development seems thave come near the end of Cretaceouime in the Mesozoic Era. As th

dinosaurs ruled the continents, so diother strange reptiles dominate the seasHad you been able to see this ancienworld, you would surely have bee

convinced that the dinosaurs and othereptiles would rule forever.

But it was not to be. The dinosau

hordes were wiped out and the reptilereduced to the position of relativnsignificance they occupy today. Such

profound and sudden change in th


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evolutionary trend of life must have haa cause, and scientists have sought itSeveral theories have been proposed t

explain extinction of dinosaurs, and theare most interesting.

At the end of Cretaceous time, some o

our great mountain ranges were formedt was a time of earthquakes and o

volcanoes that belched forth clouds o

ash and rivers of molten rock. Sompeople would say these catastrophievents killed all the dinosaurs. Thscientist shakes his head. If these event

killed dinosaurs, why not the otheanimals that lived with the dinosaursAnd what of those parts of the world thahad no volcanoes, what killed dinosaur


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here?

Changes in environments, the drainage o

akes and swamps as young mountainrose, changes in vegetation as newplants replaced old, and sudden shifts oclimate occurred. These condition

could explain local extinction, but therwere places where these changes did nooccur and yet all dinosaurs in all place

died.

A one-time favorite theory suggested thancreasing numbers of small mammal

ate dinosaur eggs, but there were manmammals eating dinosaur eggs during alof Cretaceous time and the dinosauhordes increased. Many more mammal


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during succeeding ages have not killeoff the turtles, snakes, lizards, ancrocodiles that lay eggs and exist i

great numbers today.

Some disease or combination of plaguemay have swept the dinosaurs int

extinction. If so, no evidence has beefound to date that confirms or deniesHowever, most paleontologists do no

accept this theory.

These are some of the theories that havbeen advanced to explain the sudde

extinction of dinosaurs throughout thworld. Each theory will explain thdeath of some dinosaurs in some placebut attempts to apply any of them, o


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combinations of them, to worldwidextinction have failed.

This dinosaur story is like a mysterhriller with the last pages torn out. A

most important part is missing. That irue and the paleontologist knows it. H

also knows the riddle will probablnever be solved. He might point ouhowever, that no one has successfull

explained the extinction of the passengepigeon which occurred quite recentlynor do we know why some other specieof wildlife are on the brink of extinctio

oday. The paleontologist is not the onlone who must say, “I don’t know.”


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History and Development of

the Quarry

DISCOVERY AND EARLY

YEARS

o one knows how long the old bone

had been weathering out of the hills owhat is now Dinosaur NationaMonument before the first man sawhem. Curious Indians, wanderin

between the upturned ridges o


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Mesozoic rocks, picked up fragmentand carried them off to their campwhere they are now found among th

arrow points, ax heads, and corngrinding stones. In 1776, the SpaniardFather Escalante, passed within sight ooday’s dinosaur quarry, not dreaming ohe antiquity hidden there. Maj. Joh

Wesley Powell, on his second voyagdown the Green River in 1871, recorde

he presence of “reptilian remains” ihe area, but wrote nothing more abouhem. Sheepherders, cattlemen, an

hunters observed them and wer

mpressed in proportion to theiunderstanding. But, through all the yearshe nature of the bones remained

mystery.


105/203EARL DOUGLASS, DISCOVERER OF THE


106/203

DINOSAUR QUARRY.

Then, in 1893, this mystery was solvedO. A. Peterson, a scientist from thAmerican Museum of Natural Historywhile conducting field work in the Uint

Basin to the south of the presenmonument boundaries, discovered boneout-cropping from a recognized fossilbearing stratum. The stratum was th140,000,000 year-old Morrisoformation. The bones? Peterson reportehem as the remains of dinosaurs.

That report was to have an importannfluence, 15 years later, in directing

fellow paleontologist from the Carnegi

Museum in Pittsburgh to investigate th


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area. Earl Douglass was thpaleontologist’s name. In 1908, he anW. J. Holland, Director of the Carnegi

Museum, found themselves in the regioof Peterson’s discovery, searching fodinosaur remains. They extended theisearch to the north and thence along thMorrison hogback that flanks SplMountain. Bone was found—not muchbut enough to bring Douglass back th

following summer and in company witGeorge Goodrich, a local resident, tpursue the hunt.

The hunt came to a triumphant climax oAugust 17, 1909, when—to quote froDouglass’s diary—“At last in the top ohe ledge where the softer overlyin


108/203

beds form a divide ... I saw eight of thail bones of a Brontosauru

{Apatosaurus} in exact position.”

STARTING THE QUARRYThis was the beginning—the beginninof the celebrated dinosaur quarry whic

was to yield such a multitude and varietof ancient forms to science, aneventually lead to the establishment oDinosaur National Monument.

Douglass proceeded to dig into the solirock along those original eight tail bone

and found other parts of the skeleton. I


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ime, the almost complete frame of thpatosaurus was exposed. The skul

was missing and parts of the limb bones

but this was to be expected, as fossivertebrates are rarely preserved in theientirety. What was not expected were thremains of a smaller dinosaur cominglewith those of its huge contemporary.

EXTENT AND

DEVELOPMENT OF THE

FIND

Douglass was elated. This was morhan a “one strike”! How much more


110/203

only further digging would tell. Sensina large-scale operation, he informed thCarnegie Museum of his prospects an

readied things with the intensity of a maat the gate of destiny. From thneighboring ranches he recruited menhorses, and equipment. He sent for hiwife and child. He constructed a road the discovery site, built a five-roo

cabin out of logs and lumber, converte

a sheepherder’s camp wagon into aoffice, selected ground for futurplanting, bought a cow. A forge was se

up. Tools were purchased.

Back at the museum, Andrew Carnegiehimself, evinced interest. He had alwaywanted something “as big as a barn” fo


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his institution. A special annual fielfund of $5,000 was added to the regulabudget to carry on the work.

Within a year, Douglass and his men harun a cut over a hundred feet long in thhard sandstone, digging down along th

almost perpendicular slant of the rockAt the base of this, rails were laid ansmall mine carts introduced to haul awa

he cuttings from the rapidly developinquarry.

ew specimens appeared: A smal

plant-eating dinosaur known aryosaurus; an armored form calle

Stegosaurus; and another large creaturike the Apatosaurus. Best of all, th


112/203

patosaurus No. 1 was well on its waout of the rock and would soon be reado ship to the Carnegie Museum i

Pittsburgh.

“... I SAW EIGHT OF THE TAIL BONES OF

A Brontosaurus IN EXACT POSITION.”

(FROM DOUGLASS’ DIARY, 1909.


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SHOWN IN PHOTO IS DOUGLASS’

ASSISTANT, ELDER GOODRICH.)


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THE FIRST CUT IN THE QUARRY, AS IT

LOOKED IN 1910. (COURTESY, A. S.

COGGESHALL.)


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SAMPLE VIEW OF DINOSAUR REMAINSAS THEY WERE UNCOVERED IN THE

QUARRY. THIGH BONE NEAR MAN.

(COURTESY, A. S. COGGESHALL.)


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QUARRY OPERATIONS. SAURISCHIAN

PLASTERED PELVIS UPPER CENTER.(COURTESY, A. S. COGGESHALL.)

n 1913, after 3 years of laboratory worn the Carnegie Museum the bipatosaurus was on its feet in the Hal

of Vertebrate Paleontology—1 of the

mounted specimens of this genus in th


117/203

country and the most perfect of alPrepared and erected by Arthur SCoggeshall and his associates,

measures 71½ feet long and stands 1feet tall at the arch of the back.

As the excavating progressed it was no

ong before the diggings became what iknown to the profession as a “generaquarry.” Dinosaurs of “all kinds an

sizes” were showing up. Other quarrieof this type had been developed iprevious years in the Morrisoformation at Como Bluff, Wyo., an

Canon City, Colo., but they containenothing like the variety of forms founhere. Moreover, these at the monumenwere better preserved and the skeleton


118/203

more intact.

The remains most frequently encountere

n the diggings were those of sauropod—the huge plant-feeding dinosaurs witong tapering extremities that lumbere

about on four pillar-like legs

Camarasaurus and the largepatosaurus were typical members o

his group, and their numerous bone

show them as being common animals oheir time.

More common were the Diplodoci, o

he exaggerated neck and even longewhiplash tail. This genus distinguishetself by producing not only the larges

amount of skeletal material from th


119/203

quarry, but also the largest number oskulls—those rarest of fossils. One skulwas found in exact position with th

neck bones, which settled all doubts ao the details of this animal’s head piece

The longest Diplodocus to come frohe monument extended 75½ feet.

Contrast this with the diminutivaosaurus, a 2½-foot biped which rank

as the smallest dinosaur yet taken frohe deposit. This tiny creature hahollow limb bones and was one of thagile, quick-running types. Only one wa

found. When discovered, Douglashought it a “baby” dinosaur, but stud

proved it to be a full-grown specimenThe condition of the skeleton reflecte


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considerable agitation before and afteburial. It lay on its back, the limbdistended. The tail was gone and th

skull crushed.

n many respects, the most interestindinosaur found was the sauropod

arosaurus. It was an extremely longnecked form, some of the individuacervical vertebrae measuring 3 feet i

ength. Two specimens were excavated.

The flesh-eaters, as might be expectefrom their scarcity in other localities

made but a small showing. Twspecimens of Antrodemus werunearthed. Thirty feet long, this animawas the ranking predator of its day


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although hardly comparable to thowering Tyrannosaurus that entere

upon the earthly scene at a later age.

Stegosaurus remains—so abundant thaDouglass grew tired of them—added bizarre note. An armored form, it wa

equipped with a frill of bony plates thaextended the length of the back anerminated in a pair of sharp spines. It

chief claim to fame rests in its supposewo sets of “brains,” one a motorcontrol center situated in the hip regionand the other in the usual place.

Everywhere they dug, the excavatorfound fresh material—a vast jumble obones so concentrated and intermingle


122/203

as to make it difficult to distinguish onspecimen from another. Douglass waamazed. Obviously, it was not wit

animals of a single area that he wadealing, but of an entire region. He wadealing with a dinosaur fauna. He waalso perplexed. How did so mandifferent types happen to occur in onsmall locality?

Slowly, as Douglass’s acquaintance withe deposit grew, the answer came. Iwas, he reasoned, the work of a riverThe sandstones were ancient sediments

n their structure and composition lay thstory of swift swirling currents. Thcoarse granular texture told of faswater; the crossbedding, of shiftin


123/203

channels; the grouping of the bones intclusters, of eddies.

t all added up to an old delta deposit ahe mouth of a river, a region of bar

where the carcasses of dinosaurbrought down stream accumulated

Settling, the great hulks became burieas they sank into the receptive sand. Anumber of carcasses multiplied ... an

slowly, as flesh and ligament decayedhe bones became mingled, eventually tpetrify and remain preserved through thages.

WORK METHODS


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At the quarry, excavating continuesummer and winter. The methodemployed were those tha

paleontologists had used for decadesThere was no compressed air, no laborsaving devices. The work was done bhand. The crew, which seldom exceedefour men at any one time, becamveterans in the art of fossil extractionThe bone was brittle; the encasin

sandstone, hard. It required toil, patiendirection, and a knowledge of anatomy.

Judiciously placed charges of gian

powder shattered the overburden. Handrills, wedge-and-feather, and crowbaworked the rock away, until the bonayer was encountered. The slow


125/203

attrition by hammer and chiseaccomplished the final delicatseparation of the remains from th

enclosing matrix. Team-and-scraper ansmall handcarts removed the rubble thaswiftly accumulated in the cut. As thbones were chiseled from the quarrface in large blocks of rock, they werencased in strips of burlap dipped iflour paste. (Later, plaster of Pari

supplanted the flour paste.) Then thewere lowered by rope onto a muledrawn skid and “snaked” down the trainto the gulch to await boxing.


126/203

REMOVING A LARGE THIGH BONEFROM THE QUARRY WALL DURING THE

CARNEGIE MUSEUM OPERATIONS.



127/203

PLASTERED SPECIMEN REMOVED

FROM THE QUARRY DURING THE

CARNEGIE MUSEUM OPERATIONS.


Transporting the fossils from quarry trailhead was a major undertaking. Irequired wagon trains—4-horse team


128/203

hauling high-wheeled freight wagonover 60 miles of rutted roads to DragonUtah. There the precious goods wer

oaded onto boxcars of the nowabandoned narrow gauge UintaRailway, later to be transhipped to thstandard gauge Denver & Rio Grandine at Mack, Colo.

FURTHER

DEVELOPMENT

Specimens continued to show in recorabundance, most of them duplicating thearlier finds of Diplodocus an

Stegosaurus. But there were new forms


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oo. One of them was a Camptosaurushe first to be found at the quarry. It wa

a modified biped of plant-eating habits

a little more than 10 feet long, with itskull and part of the tail missing.

By 1921 the deposit had been worked t

a length of 400 feet east and west, and ta depth of about 60 feet. Rock was beinstripped from the quarry face at the rat

of approximately 20,000 cubic feeannually, and the chisels of Douglass anhis men had penetrated to the richesbone-bearing zone.

n the following year they uncovered onof the most perfect skeletons of dinosaur ever exhumed. It was a smal


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sauropod named, Camarasaurus lentusWhen found, its 17-foot vertebracolumn was practically intact, except fo

a few tail segments. The skull was iplace, and the limbs in their approximatpositions.

t was an important find scientificallyThe position of the limbs gave cleaevidence of the manner in which thes

animals carried themselves. Tharticulation between the thigh bone anhe pelvis showed conclusively tha

sauropods walked with their legs more

or-less vertical to the body and not withe bowed-out crawling posture habituao lizards, as many scientists ha

supposed. The skull was the fines


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known for this genus. It was completeven to the sclerotic ring—a complex obony plates which surrounded the livin

eye and protected it.

As exhibit material it was without rivat was mounted as found, lying on it

side, the bones fixed in death in thmatrix in which they had been preserve—a fitting climax to the 13 consecutiv

ears that had seen an unknowsandstone ridge in Utah becomDinosaur National Monument.

n those 13 years the Carnegie Museuhad taken from the quarry parts of 30dinosaur specimens, 2 dozen of whicwere mountable skeletons. Ten differen


132/203

species were represented. It was thbest collection of Middle Mesozoimonsters in the world.

n the years that immediately followedhe still-rich “dig” was worked by tw

other organizations—the Smithsonia

nstitution and the University of Utah.


133/203

Camarasaurus SKELETON—THE MOST

PERFECT REMOVED FROM THE

QUARRY. (COURTESY, CARNEGIE

MUSEUM.)

But finally the museums had reaped thei


134/203

harvest. The fruits of the harvest hagone to enrich many of their finesdisplays. However, still buried in th

untouched part of the wall were thremains of still more dinosaurs. All thawas needed was to reveal them. The 67ilt of the rock made it a perfect exhib

face. Strip off the overlying layersexpose the skeletons, and relief them iplace. This had been Douglass’s idea a

far back as 1915, when he recorded it ihis diary.

PROTECTING THE

QUARRY


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But Douglass was not the only one trealize the necessity of preserving thiunique fossil record of the dinosaurs fo

people of today and the future to see ohe spot. Officials of the Carnegi

Museum realized the extraordinarnature of the deposits and theicontribution to our knowledge of thpast; and they were not long in takinsteps to protect the dinosaur quarry. T

preserve it for science, they sought to laclaim to it as a mineral property. Bu

heir claim was disallowed by the U. SDepartment of the Interior, becaus

fossil bones could not be classed as mineral within the meaning of the mininaws.


136/203

The museum pressed its case, this timwith results—but not what theexpected. The outcome was not th

establishment of a mere mineral claimbut of a national monument. Under thprovisions of the Antiquities Act, tsafeguard and preserve objects anareas of significant scientific or historinterest, the dinosaur quarry and 8

acres of surrounding land were declare

a national monument on October 41915. Less than a year later it wancluded in the newly created Nationa

Park System.

Several things contributed notably to thiaction to protect the quarry. They werehe exceptional preservation of th


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bones; the number, variety ancompleteness of the skeletons; threlative abundance of skulls, consistin

of 8 or more in a complete state, anabout an equal number of incompletones; and the finding of the firscomplete tails.

n 1923, knowing that the quarry waprotected, and that the scientifi

collection of the fossil bones fomuseum exhibit was at an end, EarDouglass turned again to the idea omaking a perfected exhibit of the fossil

right where they lie. His letter to DrWalcott, secretary of the Smithsonianstitution, reads, in part, “I hope that th

Government, for the benefit of scienc


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and the people, will uncover a largarea, leave the bones and skeletons irelief and house them in. It would mak

one of the most astounding annstructive sights imaginable.”

ARCHITECT’S DRAWING OF VISITOR

CENTER AT QUARRY SITE.

This is precisely what the Governmen

had in mind and, through the agency o


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he National Park Service, intended taccomplish. Plans for an in-place exhibwere drawn up. But many years were t

elapse before the plans passed froblueprint into reality.

n the meantime, the quarry entered th

second phase of its existence, a dormanperiod from a scientific viewpoint, buone in which the forces of the futur

gathered ground.

During the 1930’s the monument serveas a transient camp. A. C. Boyle wa

nstalled as resident geologist ancustodian for the Park Service. Undehis guidance a program for the generadevelopment of the area was carried on


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financed largely by WPA funds. Thientailed, among other things, thdeepening and widening of the quarr

cut, and the construction of buildingater to accommodate the monument staf

and exhibits.

The American Museum of NaturaHistory became interested in thdevelopment at this time and, through it

curator of fossil reptiles, BarnuBrown, sought to initiate a joint efforwith the Park Service for exhibiting thquarry remains.

PRESENT


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DEVELOPMENT

t was not until September 1953 that thears of Park Service planning borfruit, and the work of developing an inplace exhibit for the monument wa

begun. Many factors operated to sprinhe project into being, not the least o

which was the active interest anwholehearted support of Horace M

Albright, a former Director of thService.

Theodore E. White, formerly with thSmithsonian Institution and with HarvarUniversity, was placed in immediatcharge, under the supervision of Jess H

Lombard, the superintendent of th


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ational Monument. His task, and that ohis associates, was to expose thremaining specimens in the quarry wal

and work them out in bas-relief.

A shelter had been built over thworking space and power tools wer

ntroduced for the first time. Usincompressed air, the rock was scaled ofwith jackhammers and “paving

breakers,” until most of the overburdehad been removed. Subsequent probinnto the bone layer was done wit

smaller chipping hammers, mallet, an

chisel. This operation continued throug1954 and 1955 as, slowly and carefullyhe extent of the skeletal material wa

determined. It comprised parts o


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several large dinosaurs, sufficient iquantity to justify the next step—thconstruction of a building to enclose th

quarry face.

Erection of this unusual structure, thfirst of its design to be attempted

commenced in 1957 and it was openeo the public in the following year. Now

as one of the many development project

n its MISSION 66 program, thational Park Service has resumed thdelicate work of uncovering this corneof the ancient world and preserving it in

place for all time.


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The Scene Today

f you stand at the overlook, you will sehe Green River, Split Mountain, and

rolling plain to the south that stretches ta hazy line of mountains. To many, it i

an unfamiliar land that lies strangelsubdued beneath a blazing sun and antensely blue sky.

That blue sky is the key to the kinds oplants and animals that live in this parof the monument. They live most of theiives under blue sky, and, even whe


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clouds do form over the mountains andrift across the lowlands, the results ardisappointing. A high wind, dust an

sand, a few drops of rain, and the stor s over.

The climatic conditions under whic

ocal plants and animals live arconditions of extremes. On summer dayhe temperatures may rise above 100°

although the nights are usually cooDuring the winter, temperatures may skio 30° below zero or more. It is no

uncommon for the thermometer to remai

below zero for weeks on end. But thmost influential climatic factor is wate—and there is little of it. The totaearly precipitation is a little less than


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nches! It is interesting then to find suca wide variety of plants and animals thanot only survive but flourish under suc

rigorous conditions.

The methods used by plants in adaptino arid conditions are interesting an

varied. The wide-spreading, shallowroot system and thick stem of the cactuenhance collection and storage of water

These strange plants are quite plumpwith stored water in the spring when thsnows melt, but they gradually lose thiplumpness during the dry summer, an

by autumn many seem lifeless.

Other plants conserve their water bminimizing the loss through their leaves


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This may be done in a number of waysThe leaves of the spiny greasewood arcovered with a waxy substance tha

nhibits water loss while the leaves ohe sagebrush are covered with hairs o

fuzz that serve the same function. Theaves of the juniper are scale-like an

really don’t look like leaves at all. Thmost direct method of preventing wateoss through leaves is to drop the leave

hemselves, and this method is used to greater or lesser degree by many deserplants. The serviceberry is a gooexample of this method. In late summer

ooks dead, and yet the following sprinfinds it robed in green and covered witflowers.


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n contrast to the frugal habits of thplants just described, the cottonwoodseem lavish indeed. Usually big trees

hey spread a canopy of green in whosshade rest birds and animals alike. Havou ever rested under a cottonwood? I

so, you will remember it as being cooeven on the hottest days. Part of thcoolness was due to the hundreds ogallons of water which are transpire

hrough the leaves each day. Becauscottonwoods require so much water, theusually grow along streams or neasprings. Frequently they are seen alon

dry ravines where their thirsty roots tahe subsurface drainage that lies hidde

below. Like the other plants howeverwhen the supply of water become


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nadequate they shed their leaves anwait for the next spring. Fast growingusually of large size, and wasteful o

water where water is dear, thcottonwood seldom lives two hundreears while the twisted juniper on th

dry, rocky ledge frequently lives as mucas five hundred.


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SPLIT MOUNTAIN GORGE.

nconspicuous through most of the yeaare the flowering plants. Some of thesare annuals—plants that grow froseeds, mature, bloom, produce seeds

and die in the span of a few short weeks


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When the snows melt and the sun warmhe earth, the seeds that survived th

winter germinate. The usually barre

hillsides produce spots of green thasoon spread to form patches as more anmore plants mature. Lupine anocoweed are purple and heliotrop

splashes color along the roads, while thfragrant, white, evening-primrose dothe sandy hillside. Scarlet gilia an

ndian paintbrush add a touch of red the scene, and orange is provided by thmallow.

April, May, and early June provide thbest flower show as spring rainsupplement the moisture from meltesnow. Their races won, their seed


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produced, the annuals wither and fadaway as the temperatures rise. By thfirst of July little remains of the splendi

show.

Two plants do brighten the desert scenn August and September. Most commo

s the rabbitbrush, a plant that growalmost everywhere. It is rathenconspicuous except in late summe

when its brilliant yellow blossoms turhe whole shrub golden. The other is thbee plant of which there are twspecies: one has yellow blossoms, an

he other has purple. These tall plantgrow along washes, stream coursesroads, and irrigation ditches. Theidelicate blossoms are alway


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surrounded by insects drawn by thnectar the flowers produce in greaquantities.

These, then, are a few of the typicaplants. Each has adjusted its needs those limiting factors—winter cold

summer heat, and aridity. A great numbeof plants grow on the monument thahave not been mentioned here, but the

are like the typical plants and havsimilar ways of meeting the problems osurvival.

Many people who profess an interest inature admit they cannot get very exciteabout plants. Such disinterest may resun minimizing the importance of plants i


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he general scheme of nature. That woulbe a major error. The plants of the worlare the foundation upon which othe

forms of life are dependent. They alonare able to utilize the minerals in the soiand convert carbon dioxide and water tcarbohydrates. Because of thesabilities, the parade of life has been ablo advance only when the plant

advance. In the present as in the past, th

kinds and abundance of plants sedefinite limits as to the species annumbers of animals an area may supportThus, if man changes the plants of a

area he will surely change the animaloo, whether he realizes it or not.

f you drive to the quarry in the heat o


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he day you will see only a few of thbirds that live here. They don’t like thunt their food during those hot hours

Frequently a turkey vulture sailmajestically above the plains along thGreen River. Sometimes so high happears to be a speck, his telescopic eysearches the ground for the carrion upowhich he feeds. Another bird that doenot mind the heat is Say’s phoebe. He i

usually found perched on a fence post, wire, or a dead branch waiting for somnsect to buzz by. A graceful, short flight

a pop of his beak, and then back to hi

perch to repeat the cycle again. As hsits motionless, his gray breast andarker gray head and back make hihard to see.


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The time to watch birds is in thevening; as the sun sinks and the aicools, they come forth. Small gray

brown rock wrens hop among thboulders near the visitor center. Robinscurry through the leaves in the streacourse below the Dinosaur Quarry. Heroo, western flycatchers and Audubon’

warblers search among the cottonwoodfor insects. A flash of red and white i

seen as a red-shafted flicker darts frots nest in the hollow trunk of a tree. Th

sky is filled with wheeling, twitterinrough-winged swallows and white

hroated swifts that descend from theinests on the cliffs to feed upon the gnatand other flying insects.


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These are the birds that spend the sprinand summer here. They raise theifamilies and, young and old alike, depar

n autumn when frost kills the insectupon which they feed. As they flee thcold of winter, they are joined by manother birds that make their summehomes at higher elevations or mornorthern latitudes. Ducks, geese, answans join the hordes movin

southward. So do the various shorbirds, bluebirds, and hummingbirds.

But the sagebrush flats and brush

ravines are not left vacant by thiwholesale migration, for as the summeresidents move out the winter residentmove in. The Oregon and gray-heade


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uncos spend the entire winter hereGreat flocks of mountain bluebirddescend from the mountains and piño

ays make the hills resound with theiscreams. Canada geese and golden-eyducks live on the Green River anr