,,bureau ,,of ,,economic ,,geology ,the ,university of ,texas at ,austin ,peter ,t4 ,flawn1 ,director ,guidebook #h ,the ,geologic ,story of ,palo ,duro ,canyon ,by ,william ,h4 ,matthews ,,iii ,illustration3 ,,the ,,university ,,of ,,texas ,,at ,,austin ,august #aifi ,second ,printing ,august #aihc ,contents ,introduction #a ,acknowledgments #b ,park history #c ,ancient man in ,palo ,duro ,canyon #c ,indians of the ,plains #c ,advent of the ,white ,man #c ,regional setting #h ,the geologic story #aj ,the canyon's rocks and minerals #aj ,unraveling earth history #aj ,the geologic column and geologic time scale #ab ,geologic formations exposed in ,palo ,duro ,canyon #af ,quartermaster ,formation #ag ,tecovas ,formation #ai ,trujillo ,formation #bb ,ogallala ,formation #bc ,rocks of the ,pleistocene #bh ,how the canyon was carved #bi ,the geologic work of running water #bi ,weathering and gravity add the final touch #cj ,weathering #cj ,mass-wasting #ca ,differential erosion #ca ,what to do and see at ,palo ,duro ,canyon ,state ,park #cc ,park ,entrance #cc ,coronado ,lodge and ,observation ,point #cc ,the ,scenic ,drive #cc ,pioneer ,amphitheatre #cc ,sad ,monkey ,train ,ride #ce ,triassic ,peak #ce ,spanish ,skirts #cg ,catarina ,cave #cg ,santana's ,face #cg ,the ,sky ,ride #cg ,the ,first ,water ,crossing #ci ,colonel ,charles ,goodnight's ,dugout #ci ,the ,lighthouse #ci ,capitol ,peak #dj ,fortress ,cliff #dj ,the ,rock ,garden #dj ,the ,devil's ,slide #dj ,the ,turnaround #da ,hiking #dc ,horseback riding #dc ,camping and picnicking #dc ,photography #dc ,panhandle-,plains ,historical ,museum #de ,selected references #dg ,glossary #dh ,index #ej ,illustrations ,figures-- ,page #a4 ,aerial ,view of ,palo ,duro ,canyon ,frontispiece #b4 ,place map of ,palo ,duro ,canyon #d-e #c4 ,indian carving on sandstone boulder #f #d4 ,war dress of ,comanche ,chief ,quanah ,parker #g #e4 ,generalized geologic map of the ,texas ,panhandle #i #f4 ,geologic time scale #aa #g4 ,generalized geologic map of ,palo ,duro ,canyon ,state ,park #ad-ae #h4 ,joints and gypsum veins in ,quartermaster ,formation #ag #i4 ,syncline in ,quartermaster red beds #ah #aj4 ,reduction halos in ,quartermaster shale #bj #aa4 ,cross-bedded boulder of ,trujillo sandstone #bj #ab4 ,panoramic view of canyon showing major rock units exposed in canyon #ba #ac4 ,phytosaur skull #bb #ad4 ,skeleton of ,buettneria #bd #ae4 ,mortar hole made by ,indians #be #af4 ,rock pedestal near the ,lighthouse #be #ag4 ,outcrop of ,ogallala caliche #bf #ah4 ,life-sized model of shovel-jawed mastodon #bg #ai4 ,fossilized carapaces of ,pliocene tortoises #bg #bj4 ,talus slopes and 8hoodoo0 on ,capitol ,peak #ca #ba4 ,entrance to ,palo ,duro ,canyon ,state ,park #cd #bb4 ,coronado ,lodge #cd #bc4 ,pioneer ,amphitheatre #ce #bd4 ,train on ,sad ,monkey ,railroad track #cf #be4 ,south face of ,triassic ,peak #cf #bf4 ,spanish ,skirts #cg #bg4 ,catarina ,cave #ch #bh4 ,santana's ,face #ch #bi4 ,picnic area at first water crossing #ci #cj4 ,colonel ,charles ,goodnight's ,dugout #dj #ca4 ,the ,lighthouse #da #cb4 ,capitol ,peak #db #cc4 ,fortress ,cliff #db #cd4 ,the ,rock ,garden #dc #ce4 ,the ,devil's ,slide #dd #cf4 ,campsite in south end of park #dd #cg4 ,entrance to ,panhandle-,plains ,historical ,museum #de ,illustration3 ,fig4 #a4 ,aerial view of ,palo ,duro ,canyon showing location of major points of interest3 7#a7 ,coronado ,lodge2 7#b7 ,triassic ,peak2 7#c7 ,timber ,mesa2 7#d7 ,capitol ,peak2 7#e7 ,fortress ,cliff2 7#f7 ,prairie ,dog ,town ,fork of ,red ,river2 7#g7 ,the ,turnaround 7termination of ,park ,road #e74 7,courtesy of ,charles ,a4 ,wolfin2 photograph by ,w4 ,a4 ,hester47 ,the ,geologic ,story of ,palo ,duro ,canyon ,william ,h4 ,mathews ,,iii#a ,,introduction ,like the early ,spanish explorers who first saw ,palo ,duro ,canyon1 today's visitor is likely to view the impressive canyon with surprise and awe4 ,this great depression--it is more than #b miles wide and as much as #hjj feet deep within park boundaries--contains a fascinating assortment of multicolored geologic formations and erosion-produced rock sculptures of many shapes1 colors1 and size4 ,the geographic setting of the canyon further heightens its impact on the visitor1 for it is surrounded by the level1 virtually treeless plains of the ,texas ,panhandle4 7,see upper background area in fig4 #a1 frontispiece74 ,it is not surprising that this scenic area has been set aside as a ,state park1 for ,palo ,duro ,canyon has long been of interest to man4 ,first1 as the hunting grounds of prehistoric ,indians who stalked the now-extinct ,ice ,age mammoths and bison that roamed the valley floor4 ,later1 the canyon was frequented by the ,comanches1 ,apaches1 ,kiowas1 and other ,indians of historic time4 ,these tribes1 like those before them1 found both food and refuge within the canyon4 ,however1 it was not until #ahgf that ,palo ,duro ,canyon was inhabited by the white man4 ,it was during this year that pioneer cattleman ,charles ,goodnight herded some #a1fjj head of cattle into the canyon and established a camp there 7p4 #f74 ,today's visitor to ,palo ,duro ,canyon can re-live some of the fascinating history of this interesting area4 ,one can still see a replica of ,colonel ,goodnight's primitive dugout1 follow the faint trace of the ,comanche ,trail1 or perhaps find the fossil bones of prehistoric creatures that lived hundreds of thousands--even millions--of years ago4 ,but most visitors to ,texas' most colorful canyon are not attracted by its interesting history4 ,they come instead to enjoy the scenery and recreational opportunities that are present4 ,these are readily accessible1 for a carefully engineered1 hard-surface road leads from the rim of the canyon to the canyon floor4 ,there are campgrounds1 picnic areas1 concessions1 and even an outdoor theatre 7fig4 #bc74 ,the location of these facilities and some of the canyon's more interesting geologic features are shown on the generalized place map of the canyon 7fig4 #b74 ,this publication does not attempt to describe the scenic beauty of ,palo ,duro ,canyon1 for this must be seen to be appreciated4 ,rather1 it discusses the geologic setting and origin of the canyon1 the methods by which some of the more interesting geologic features were formed1 and briefly reviews the history of the area4 ,hopefully1 it will enable the visitor to understand better the meaning behind the canyon scenery1 thereby enhancing his visit4 ,,acknowledgments ,many people have assisted in the preparation of ,the ,geologic ,story of ,palo ,duro ,canyon1 and their help is gratefully acknowledged3 ,professor ,jack ,t4 ,hughes1 ,dr4 ,frank ,w4 ,daugherty1 ,dr4 ,robert ,c4 ,burton1 ,meade ,humphries1 and ,jim ,hughes of the ,west ,texas ,state ,university ,geology ,department provided much information about the area and assisted in the field2 help was also provided by ,mr4 ,pete ,cowart1 ,mr4 ,earl ,burtz1 ,mr4 ,jerry ,tschauner1 ,mr4 ,bob ,watson1 ,mr4 ,king1 and other park personnel2 ,mr4 ,c4 ,boone ,mc,clure1 of the ,panhandle-,plains ,historical ,museum1 furnished some of the photographs2 ,mr4 ,j4 ,dan ,scurlock1 ,mr4 ,bill ,collins1 and ,mr4 ,harold ,allums1 of the ,texas ,parks and ,wildlife ,department1 made available certain maps and statistical data2 ,mrs4 ,ples ,harper of ,canyon assisted in assembling information and photographs for the ,pioneer ,amphitheatre2 and the aerial photograph of ,palo ,duro ,canyon was taken by ,mr4 ,w4 ,a4 ,hester and made available through the courtesy of ,mr4 ,charles ,a4 ,wolflin of ,amarillo4 ,drs4 ,peter ,t4 ,flawn1 ,peter ,u4 ,rodda1 and ,ross ,a4 ,maxwell of the ,bureau of ,economic ,geology read much of the manuscript and offered many helpful suggestions1 and ,mr4 ,a4 ,richard ,smith provided special information on caves in the ,palo ,duro area4 ,special thanks are due to ,miss ,josephine ,casey who edited the manuscript and to ,mr4 ,j4 ,w4 ,macon1 cartographer1 who assumed responsibility for preparing the maps4 ,thanks are due also to my wife1 ,jennie1 who critically read the manuscript and took a number of the photographs4 ,finally1 ,i would like to thank ,dr4 ,j4 ,daniel ,powell of ,the ,university of ,texas at ,arlington for invaluable assistance in the field and his enthusiastic co-operation throughout the project4 ,,park ,,history ,palo ,duro ,canyon's long and colorful past has created considerable interest among historians1 archeologists1 and geologists4 ,historians have traced the written history of man and his effect on the ,palo ,duro area1 but archeologists have delved much further into the past4 ,they have sought out and studied the more enduring records of the canyon's early inhabitants--their tools1 utensils1 and weapons4 ,the geologist1 however1 is interested in history that far antedates even the most primitive human inhabitant of the canyon4 ,the earth scientist has probed the geologic record of the ,palo ,duro area1 using rocks1 minerals1 and fossils as clues to the geologic history and development of the canyon4 ,palo ,duro ,canyon is unique among ,texas' ,state parks because of its many contributions to history1 archeology1 and geology4 ,here the written record1 the artifacts of prehistoric man1 and the geologic formations overlap and complement each other in many respects4 ,although this guidebook is primarily concerned with the geologic history of the canyon1 a brief review of its human history is also included4 ,,ancient ,,man ,,in ,,palo ,,duro ,,canyon ,archeological studies indicate that the earliest known inhabitants of ,palo ,duro ,canyon lived in the canyon from about #aj1jjj to #e1jjj ,b4,c4 ,these early men apparently hunted the bison and now-extinct elephant-like mammoths that roamed the ,palo ,duro area during the ,ice ,age of ,pleistocene time 7see geologic time scale1 fig4 #f74 ,their stone weapons and other artifacts have been found in and around the canyon4 ,it is assumed that these primitive people--like those who came later--were attracted by the streams and springs that are found in the canyon and by game that came there to feed4 ,there is also evidence that the ,indians took advantage of certain of the canyon's geologic features4 ,they fashioned tools1 weapons1 and utensils from the rocks exposed in the canyon and used certain of the shallow caves and rock shelters as their homes4 ,,indians ,,of ,,the ,,plains ,various tribes of ,plains ,indians of historic times also used ,palo ,duro ,canyon as a camping ground4 ,the presence of these ,indians is known from many campsites and burials4 ,in addition1 flint chips and stone artifacts1 potsherds1 ornaments of shell and bone1 grinding slabs1 stone mortars 7fig4 #ae71 and a few pictographs 7fig4 #c7 have provided considerable information about the culture of these people4 ,among the tribes believed to have frequented the canyon at various times are the ,apaches1 ,cheyennes1 ,arapahos1 ,kiowas1 and ,comanches4 ,however1 it is the ,comanches who are most closely associated with the ,palo ,duro area1 for the canyon is located near the center of their last homeland4 ,indeed it was here that the ,comanches were finally defeated and driven from this part of the ,plains4 ,the battlefield where ,colonel ,ranald ,mackenzie's troops fought the ,comanches is located near the southeast corner of the park 7see fig4 #g74 ,this skirmish1 which took place in #ahgd1 is believed to have been the last major ,indian battle in ,texas4 ,although most of the canyon's archeological sites have been picked over and many of the artifacts removed1 important finds are still occasionally reported4 ,park visitors who make discoveries of this type are urged to report them to a park ranger in order that they might be called to the attention of the proper authorities4 ,,advent ,,of ,,the ,,white ,,man ,although the history of ,palo ,duro ,canyon is rich in ,indian lore1 it was the coming of the white man that heralded the development of the area4 ,today it is generally believed that ,francisco ,vasquez de ,coronado was the first white man to view the canyon4 ,coronado and his men are thought to have camped here during the winter of #aeda1 as they crossed the ,high ,plains in search of the fabled ,seven ,cities of ,cibola4 ,illustration3 ,fig4 #b4 ,place map of ,palo ,duro ,canyon4 ,later1 during the #agth and #ahth centuries1 the canyon was a favorite resting place of the buffalo hunters and ,indian traders who frequented the ,plains4 ,the canyon was also popular during the first half of the #aith century1 for it was then that it was occupied by the ,comanches and served as a trade center for the ,spaniards and ,indians who came from ,new ,mexico4 ,these traders1 called comancheros1 bartered for loot taken by the ,comanches on their raids of early settlements and wagon trains that passed through the ,panhandle-,plains region4 ,this same era marked the beginning of ,american interest in the ,palo ,duro country4 ,during this period the area was visited by several expeditions including those of ,long and ,pike and the ,texas-,santa ,fe ,expedition of #ahda4 ,however1 the canyon was not fully explored or mapped until #aheb4 ,this important survey was carried out by a party which was under the supervision of ,captain ,r4 ,b4 ,marcy4 ,but it was not until #ahgf that the first white man established permanent residence in ,palo ,duro ,canyon4 ,in #ahgf--;just two years after ,mc,kenzie's rout of the ,comanches--,colonel ,charles ,goodnight herded more than #a1fjj head of cattle into the canyon4 ,here he laid out his first permanent ranch and lived in a primitive earthen dugout4 ,not only was ,goodnight's ,palo ,duro ,ranch the first in the canyon1 it is also thought to have been the first commercial cattle ranch in the ,texas ,panhandle4 ,in later years ,colonel ,goodnight formed a partnership with ,john ,adair of ,ireland1 and together they developed the famous ,,ja ,ranch--a vast spread of some #fjj1jjj acres4 ,today's visitor to ,palo ,duro ,canyon can visit a partially restored dugout similar to that occupied by the canyon's early settlers 7fig4 #cj74 ,illustration3 ,fig4 #c4 ,the face carved on this boulder can be seen along the track of the ,sad ,monkey ,railroad 7p4 #ce74 ,it is believed to have been carved by ,indians4 ,illustration3 ,fig4 #d4 ,the war bonnet1 war lance1 and head feathers of ,comanche ,chief ,quanah ,parker can be seen at the ,panhandle-,plains ,historical ,museum in ,canyon4 7,photograph courtesy ,panhandle-,plains ,historical ,museum47 ,from the late #ahjjs until about #aicj1 the ,palo ,duro country remained the domain of the ,panhandle-,plains cattleman4 ,it was1 nonetheless1 a favorite picnic and camping spot of the residents of nearby towns and cities4 ,in #aicc the recreational potential of the canyon was finally recognized and land for the ,palo ,duro ,canyon ,state ,park was purchased by the ,state of ,texas with money obtained through a public revenue bond issue4 ,today1 most of the park revenue received through gate admissions1 concession receipts1 and mineral leases goes into a fund that pays off the remaining balance of the revenue bonds4 ,during the initial phase of the park's development1 most of the improvements in the area were made by members of the ,civilian ,conservation ,corps who worked under the supervision of the ,national ,park ,service4 ,currently1 ,palo ,duro ,canyon ,state ,park is visited by approximately #cjj1jjj visitors each year and is one of the ,state's more popular recreational and scenic areas4 ,,regional ,,setting ,palo ,duro ,canyon ,state ,park is located in the ,panhandle of ,texas 7fig4 #e7 approximately #ac miles east of ,canyon on ,state ,highway #bag 7see fig4 #g74 ,it is about #ab miles south and #h miles east of ,amarillo via ,ranch ,road #aeda which intersects ,state ,highway #bag4 ,the park includes more than #ae1jjj acres of ,palo ,duro ,canyon1 a complexly dissected area which spreads into ,randall1 ,armstrong1 and ,briscoe counties4 ,more specifically1 the ,palo ,duro area is situated on the ,llano ,estacado or ,high ,plains area which comprises approximately #bj1jjj square miles of ,texas and ,new ,mexico 7see fig4 #e74 ,generally speaking1 the ,llano ,estacado is a high isolated plateau or broad mesa1 rising above the surrounding rolling plains in a nearly flat1 island-like mass4 ,on the west1 southwest1 and south1 the ,llano ,estacado is bounded by the valley of the ,pecos ,river1 while its eastern escarpment is drained by the headwaters of the ,red1 ,brazos1 and ,colorado ,rivers4 ,the rim of ,palo ,duro ,canyon is formed by the ,eastern ,caprock ,escarpment4 ,caprock is the term used to describe a massive layer of calcareous rock which supports the ,high ,plains surface 7see p4 #bf74 ,because it is more resistant to forces of erosion than the softer1 underlying more or less horizontal strata1 the caprock forms an abrupt1 precipitous escarpment at the edge of the ,high ,plains4 ,with the exception of the resistant caprock1 however1 the surficial deposits on the ,high ,plains are for the most part unconsolidated sediments4 ,the ,llano ,estacado is essentially devoid of native trees and is characterized by a sparse1 but uniform1 covering of grasses4 ,the surface rocks are of ,tertiary and ,quaternary age 7see geologic time scale1 fig4 #f7 and have a general easterly to southeasterly slope of about #i feet per mile4 ,in the vicinity of ,palo ,duro ,canyon1 rocks of ,late ,cenozoic age are directly underlain by ,permian and ,triassic formations4 ,these ,permian and ,triassic rocks1 which are discussed elsewhere in this publication1 are not normally exposed except in deeply eroded areas such as the canyon4 ,illustration3 ,fig4 #e4 ,generalized geologic map of the ,texas ,panhandle showing location of ,palo ,duro ,canyon4 ,showing3 ,q ,t ,pleistocene and ,pliocene undifferentiated ,trdo ,dockum ,group 7,triassic7 ,p ,permian undifferentiated ,,the ,,geologic ,,story ,,the ,,canyon',s ,,rocks ,,and ,,minerals ,palo ,duro visitors--regardless of age--seem to have an innate curiosity about the canyon's rocks4 ,this is not surprising1 for most of the features of the park landscape are composed of or have been sculptured from solid rock4 ,in short1 much of the natural beauty of ,palo ,duro ,canyon has been derived from the character of its exposed rock formations and the effect of geologic agents upon them4 ,because rocks are the raw materials of geology and the stuff from which landscapes are formed1 it will be helpful for the visitor to know something about the general characteristics of rocks and their role in the development of the landscape4 ,rock is everywhere around us and is one of the most common objects in the world1 yet few people can actually define a rock4 ,so1 at the outset it should be stated that a rock is a naturally formed aggregate of minerals1 and a mineral is a naturally occurring substance which has a fairly definite chemical composition1 distinctive physical properties1 characteristic internal structure1 and which commonly occurs in definite shapes called crystals4 ,although not an exact scientific or legal definition of a mineral1 the above explanation is satisfactory for the purposes of this publication4 ,although most visitors show considerable interest in the canyon's rocks and minerals1 few of them know the story behind the rocks4 ,they do not know how the rocks were formed1 of what they are composed1 how they change1 and how they differ4 ,more important1 they fail to realize the historical significance of the rocks and how they can be used to interpret events that occurred in the canyon many millions of years ago4 ,thus1 before one studies the geologic story of ,palo ,duro ,canyon1 it is helpful to know something about the various kinds of rocks4 ,there are three major classes of rocks in the earth's crust3 igneous1 sedimentary1 and metamorphic rocks4 ,igneous rocks solidified from an original molten state4 ,common examples of igneous rocks include granite1 basalt1 and volcanic ash4 ,although no igneous rocks are found in ,palo ,duro ,canyon1 they are widely exposed in parts of ,west and ,central ,texas4 ,metamorphic rocks were originally igneous or sedimentary in origin4 ,however1 these rocks have undergone such great physical and chemical change that they have been transformed into a different kind of rock4 ,thus1 metamorphic changes alter limestone to marble or sandstone to quartzite4 ,no metamorphic rocks crop out in the canyon1 but1 like the igneous rocks1 they are common in some parts of the ,state4 ,all of the geologic formations exposed in ,palo ,duro ,canyon are composed of sedimentary rocks4 ,these are rocks that have been formed by the compaction and cementation of rock and mineral fragments called sediments1 or by the precipitation of material from solution4 ,sandstone1 conglomerate1 shale1 and caliche 7see p4 #bf7 are examples of sedimentary rocks that are exposed in the canyon4 ,sedimentary rocks are typically stratified1 that is1 they occur in layers or beds called strata4 ,in addition1 sedimentary rocks--especially those of marine origin--commonly contain fossils4 ,these fossils are traces or evidence of prehistoric plants and animals that have been preserved in the rocks1 and they may provide clues as to the age of rocks and the manner in which they were formed4 ,fossil remains have been found at a number of places in the park and these are discussed later4 ,,unraveling ,,earth ,,history ,in order to understand better the geologic history and development of the canyon1 one should also have some knowledge of the basic principles of earth history and should be familiar with the geologic time scale 7fig4 #f74 ,illustration3 ,fig4 #f4 ,geologic time scale4 ,reproduced from ,,fossils3 ,an ,introduction to ,prehistoric ,life1 ,william ,h4 ,matthews ,,iii1 ,barnes and ,noble1 ,inc41 #aifb4 ,,geologic ,,time ,,scale ,,era ,,period ,,epoch ,,succession ,,of ,,life ,,cenozoic 8,,recent ,,life0 ,,quaternary #j-a ,,million ,,years ,recent ,pleistocene ,,tertiary #fb ,,million ,,years ,pliocene ,miocene ,oligocene ,eocene ,paleocene ,,mesozoic 8,,middle ,,life0 ,,cretaceous #gb ,,million ,,years ,,jurassic #df ,,million ,,years ,,triassic #di ,,million ,,years ,,paleozoic 8,,ancient ,,life0 ,,permian #ej ,,million ,,years ,,carboniferous ,,pennsylvanian #cj ,,million ,,years ,,mississippian #ce ,,million ,,years ,,devonian #fj ,,million ,,years ,,silurian #bj ,,million ,,years ,,ordovician #ge ,,million ,,years ,,cambrian #ajj ,,million ,,years ,,precambrian ,,eras ,,proterozoic ,,era ,,archeozoic ,,era ,,approximate ,,age ,,of ,,the ,,earth ,,more ,,than #d ,,billion #eej ,,million ,,years ,the geologist has learned that the earth's physical features have not always been as they are today4 ,it is known1 for example1 that mountains now occupy the sites of ancient seas4 ,coal is now being mined where swamps existed many millions of years ago4 ,furthermore1 the earth's plants and animals have also been subject to great change4 ,the trend of this organic change is1 in general1 toward more complex and advanced forms of life4 ,however1 some forms have remained virtually unaltered while others have become extinct at different points in geologic time4 ,in order to interpret earth history1 the earth scientist gathers evidence of the great changes in climate1 geography1 and life that took place in the geologic past4 ,he does this by studying the rock formations1 the structural relationships of these formations1 and the landforms of the area4 ,the record of ancient events is pieced together by studying the stony layers of the earth as one might study a giant history book4 ,indeed1 the sedimentary rocks are the rocky 8pages0 of earth history1 for in them we find the tracks and trails1 and bones and stones1 which reveal the intriguing story of life long ago4 ,much of the basic information which the geologist uses to reconstruct the geologic history of a region comes from his examination and interpretation of bedrock outcrops4 ,bedrock is the solid unweathered rock which underlies loose earth material such as soil1 sand1 and gravel4 ,an outcrop1 or exposure1 is a place where bedrock is exposed at the surface4 ,the first chapter of earth history begins with the most ancient rocks known4 ,because they were formed early in geologic time1 these rocks are normally found deeply buried beneath younger rocks which have been deposited on top of them4 ,it is for this reason that earth history is read from the bottom up1 for the earliest formed rock layers correspond to the opening chapter in our earthen history book4 ,the later chapters are found in the upper younger rocks which are located nearer the surface4 ,thus1 in 8reading0 the geologic history of ,palo ,duro ,canyon we start with the oldest 8chapter0 which is recorded in the ,quartermaster ,formation 7p4 #ag7 of ,permian age1 for these are the oldest rocks exposed in the canyon4 ,but deciphering earth history is not as simple as it might appear4 ,in many areas the rock layers are not always found in the sequence in which they were originally deposited4 ,in places1 great structural disturbances have caused some of the rocky 8pages0 to become shuffled and out of place2 others may be missing completely4 ,many rocks have been destroyed by weathering and erosion or greatly altered by metamorphism4 ,as a result1 the story recorded in these particular rocks is lost forever4 ,these missing 8pages0 make the ancient story even more difficult to interpret so the geologist must then depend on other evidence that will permit him to 8fill in the blanks40 ,the record revealed in the rocks indicates that our planet is at least #d billion years old and that life has been present for more than #c billion years4 ,during this vast span of time the earth and its inhabitants have undergone many changes4 ,,the ,,geologic ,,column ,,and ,,geologic ,,time ,,scale ,the geologic column refers to the total succession of rocks1 from the oldest to the most recent1 that are found in the entire earth or in a given area4 ,for example1 the geologic column of ,texas includes all rock divisions known to be present in the ,state4 ,by the same token1 the geologic column of ,palo ,duro ,canyon consists of the geologic formations exposed there4 ,thus1 by referring to the geologic column previously determined for a specific area1 the geologist can determine what type of rock he might expect to find in that particular region4 ,the geologic time scale 7fig4 #f7 is composed of named intervals of geologic time during which were deposited the rocks of the geologic column4 ,these time intervals bear the same names that are used to distinguish the various units of the geologic column4 ,for example1 one can speak of ,permian time 7referring to the geologic time scale7 or of ,permian rocks 7referring to rock units of ,permian age in the geologic column74 ,both the geologic column and the geologic time scale are based upon the principle of superposition4 ,this basic geologic concept states that unless a series of sedimentary rock has been overturned1 a given rock layer is older than the strata above it1 and younger than all of the layers below it4 ,thus1 the field relationship of the rocks plus the type of fossils 7if present7 give the geologist some indication of the relative age of the rocks4 ,relative age does not imply age in years2 rather1 it fixes age in relation to other events that are recorded in the rocks4 ,within recent years1 however1 it has become possible to assign ages in years to certain rock units4 ,this is accomplished by a system of rock dating based on very precise measurements of amounts of radioactive elements 7such as uranium74 ,when present in the rocks1 radioactive minerals change or decay at a known rate so that they are natural 8clocks40 ,this method of dating has made it possible to devise a time scale in years which gives some idea of the tremendous amount of time that has passed since the oldest known rocks were formed4 ,it has also been used to verify the previously determined relative ages of the various rock units4 ,the largest unit of geologic time is an era1 and each era is divided into smaller time units called periods4 ,a period of geologic time is divided into epochs1 which1 in turn1 may be subdivided into still smaller units4 ,the geologic time scale might be roughly compared to the calendar in which the year is divided into months1 months into weeks1 and weeks into days4 ,unlike years1 however1 geologic time units are arbitrary and of unequal duration1 and the geologist cannot be positive about the exact length of time involved in each unit4 ,the time scale does1 however1 provide a standard by which he can discuss the age of fossils and their surrounding rocks4 ,by referring to the time scale it may be possible1 for instance1 to state that a certain event occurred during the ,paleozoic ,era in the same sense that one might say that something happened during the ,american ,revolution4 ,there are five eras of geologic time1 and each has been given a name that is descriptive of the degree of life development that characterizes that era4 ,hence1 ,paleozoic means 8ancient-life0 and the era was so named because of the relatively simple and ancient stage of life development4 ,the eras1 a guide to their pronunciation1 and the literal translation of each name is shown below4 ,cenozoic 7,,see-no-zo-ic7--8recent-life0 ,mesozoic 7,,mes-o-zo-ic7--8middle-life0 ,paleozoic 7,,pay-lee-o-zo-ic7--8ancient-life0 ,proterozoic 7,,pro-ter-o-zo-ic7--8earlier-life0 ,archeozoic 7,,ar-kee-o-zo-ic7--8beginning-life0 ,archeozoic and ,proterozoic rocks are commonly grouped together and referred to as ,precambrian in age4 ,in most places ,precambrian rocks have been greatly contorted and metamorphosed1 and the record of this portion of earth history is most difficult to interpret4 ,precambrian time represents that portion of geologic time from the beginning of earth history until the deposition of the earliest fossiliferous ,cambrian strata4 ,precambrian time probably represents as much as #he percent of all geologic time4 ,the oldest era is at the bottom of the time scale because this part of geologic time transpired first and was then followed by the successively younger eras which are placed above it4 ,this is1 of course1 the order in which the various portions of geologic time occurred and during which the corresponding rocks were formed4 ,as mentioned above1 each of the eras has been divided into periods1 and most of these periods derive their names from the regions in which the rocks of each were first studied4 ,for example1 the ,pennsylvanian rocks of ,north ,america were first studied in the ,state of ,pennsylvania4 ,illustration3 ,fig4 #g4 ,generalized geologic map of ,palo ,duro ,canyon ,state ,park4 ,,explanation ,q ,t ,pleistocene and ,pliocene undifferentiated ,rdo ,dockum ,group ,p ,permian undifferentiated ,the ,paleozoic ,era has been divided into seven periods of geologic time4 ,with the oldest at the bottom of the list1 these periods and the source of their names are3 ,permian 7,,pur-me-un7--from the ,province of ,perm in ,russia ,pennsylvanian 7pen-sil-,,vain-yun7--from the ,state of ,pennsylvania ,mississippian 7miss-i-,,sip-i-un7--from the ,upper ,mississippi ,valley ,devonian 7de-,,vo-ni-un7--from ,devonshire1 ,england ,silurian 7si-,,loo-ri-un7--for the ,silures1 an ancient tribe of ,britain ,ordovician 7or-doe-,,vish-un7--for the ,ordovices1 an ancient tribe of ,britain ,cambrian 7,,kam-bri-un7--from the ,latin word ,cambria1 meaning ,wales ,the ,carboniferous ,period in ,europe includes the ,mississippian and ,pennsylvanian ,periods of ,north ,america4 ,although this classification is no longer used in the ,united ,states1 the term ,carboniferous is found in many of the earlier geological publications and on many of the earlier geologic maps4 ,the periods of the ,mesozoic ,era and the source of their names are3 ,cretaceous 7cre-,,tay-shus7--from the ,latin word creta1 meaning chalky ,jurassic 7joo-,,ras-ik7--from the ,jura ,mountains of ,europe ,triassic 7try-,,ass-ik7--from the ,latin word triad1 meaning three ,the ,cenozoic periods derived their names from an old outdated system of classification which divided all of the earth's rocks into four groups4 ,the two divisions listed below are the only names of this system which are still in use3 ,quaternary 7kwah-,,tur-nuh-ri7 ,tertiary 7,,tur-shi-ri7 ,although the units named above are the major divisions of geologic time and of the geologic column1 the geologist generally works with smaller units of the column called geologic formations4 ,a geologic formation is a unit of rock that is recognized by certain physical and chemical characteristics4 ,a formation is generally given a double name which indicates both where it is exposed and the type of rock that makes up the bulk of the formation4 ,for example1 the ,beaumont ,clay is a formation consisting of clay deposits that are found in and around ,beaumont1 ,texas4 ,for convenience in study1 two or more successive and adjoining formations may be placed together in a group4 ,thus1 the ,tecovas and ,trujillo ,formations have been placed in the ,dockum ,group4 ,likewise1 a formation may be subdivided into smaller units such as members1 which may also be given geographic or lithologic 7rock type7 names4 ,,geologic ,,formations ,,exposed ,,in ,,palo ,,duro ,,canyon ,as noted above1 all of the rocks which crop out in ,palo ,duro ,canyon are sedimentary in origin4 ,they represent four different geological periods3 the ,permian1 ,triassic1 ,tertiary1 and ,quaternary 7fig4 #ab74 ,although these rock formations differ considerably in composition and age1 they do not tell the whole geologic story of the area4 ,long spans of geologic time are not represented by rock units because the region was undergoing erosion or no sediments were being deposited during certain portions of geologic time4 ,rocks that had formed during one geologic period were removed by erosion during a later period4 ,thus1 segments of the geologic record were destroyed or never recorded4 ,for this reason1 much of the geologic history of the ,palo ,duro area is unrecorded and must be inferred from fragmentary evidence borrowed and pieced together from adjacent areas4 ,even so1 an interesting story can be assembled from the rocks that remain in the canyon today4 ,in general1 the following descriptions of the formations exposed in ,palo ,duro ,canyon ,state ,park follow the procedure that most geologists use in presenting the results of their geologic investigations4 ,the more distinctive characteristics of the rock units are described in order that they may be more easily recognized1 and the ways in which the rocks were formed are also considered4 ,with this background it is then possible to review the geologic history recorded in the bedrock of the canyon4 ,a simplified geologic map is presented in figure #g2 this shows the distribution of the major rock types in the canyon4 ,the reader will find it helpful to refer to this map when reading the descriptions of the various formations4 ,quartermaster ,formation4-- ,the oldest formation exposed in the canyon is the ,quartermaster ,formation of ,permian age 7see fig4 #f7 which is named from exposures along the banks of ,quartermaster ,creek in ,roger ,mills ,county1 ,oklahoma4 ,one of the more colorful formations in the park1 the ,quartermaster is composed primarily of brick-red to vermilion shales which are interbedded with lenses of gray shales1 clays1 mudstones1 and sandstones4 ,averaging about #fj feet thick where exposed in the park1 the ,quartermaster forms the floor and lower walls of the canyon4 ,the rocks of this formation are easily examined at many places throughout the canyon and in them can be seen a number of interesting geologic phenomena4 ,probably the most noticeable of these features are the shining white veins of gypsum that lace the face of the red shale outcrops 7fig4 #h74 ,a soft1 transparent to translucent mineral that can be scratched by a fingernail1 gypsum is hydrous calcium sulfate 7,ca,s,o#b;,h,o74 ,three varieties of gypsum are found in the canyon3 7#a7 satin spar1 a fibrous variety with a silky sheen2 7#b7 selenite1 a colorless1 transparent variety which commonly occurs in sheet-like masses2 and 7#c7 a fine-grained massive variety called alabaster4 ,satin spar is the most common variety of gypsum present and it commonly occurs in thin bands interbedded with the mudstones and sandstones4 ,it is much more noticeable in the shales1 however1 for it is typically seen in narrow veins which criss-cross the surface of the outcrop and intersect the bedding planes at various angles4 ,although normally white1 some of the satin spar has a soft pink or bluish hue due to the presence of impurities in the mineral4 ,illustration3 ,fig4 #h4 ,veins of selenite gypsum 7top arrow7 in ,quartermaster ,formation4 ,notice diagonal joint to left of geologist's hand 7lower arrow74 ,the presence of gypsum in the ,quartermaster red beds is of special significance to the geologist1 for it provides valuable information about the geologic history of the ,palo ,duro area4 ,it is known1 for example1 that when a landlocked body of sea water in an arid climate becomes separated from the ocean1 one of the most common salts to precipitate is hydrous calcium sulfate1 or gypsum4 ,gypsum may also be precipitated when a lake without an outlet evaporates in an arid climate4 ,geologic evidence suggests that the sediments which gave rise to the rocks of the ,quartermaster ,formation were deposited in a landlocked arm of the sea during the latter part of the ,permian ,period4 ,as evaporation continued and the sea water was reduced to approximately one-third of its original volume1 gypsum was precipitated4 ,there must have been periodic influxes of silt- and mud-bearing waters entering the ancient ,permian sea1 for layers of shale and mudstone are interbedded with the gypsum4 ,it is believed that much of the satin spar and selenite gypsum was originally anhydrite 7,ca,s,o74 ,unlike gypsum1 anhydrite does not contain water1 but it can be changed to gypsum in the presence of moisture4 ,there are two lines of evidence that indicate an anhydrite origin for the ,quartermaster gypsum4 ,first1 microscopic examination of gypsum samples reveals the presence of residual anhydrite crystals embedded in the gypsum4 ,second1 many of the gypsum beds have been squeezed into rather gentle folds4 ,these consist of small anticlines1 upfolds or arches1 and synclines1 downfolds or troughs 7fig4 #i74 ,it has been suggested that this folding took place as the anhydrite underwent hydration1 or took on water4 ,as hydration occurred and the anhydrite was converted to gypsum1 the gypsum expanded1 thereby exerting both lateral and vertical pressure on the beds around it4 ,this produced the crumpled1 wave-like folding so characteristic of certain of the gypsum beds4 ,however1 there is not complete agreement that the folding in the gypsum is due to the hydration of anhydrite4 ,certain geologists attribute this deformation to slumping caused by solution cavities1 for gypsum is relatively easily dissolved in water4 ,as the gypsum was dissolved and carried away in solution1 the removal of the supporting layers of gypsum permitted slumping and consequent deformation in the overlying shales and mudstones4 ,although some geologists believe that the folds were caused by expansion due to the hydration of anhydrite and others support deformation related to the removal of soluble gypsum1 there is general agreement that the folding is local and not related to regional or widespread deformation4 ,illustration3 ,fig4 #i4 ,sagging beds of ,quartermaster ,formation have produced this gentle syncline1 or downfolding1 in the rocks4 ,the 8dome0 on ,capitol ,peak can be seen in the background4 ,not all of the red ,quartermaster shales are uniformly colored4 ,some of them contain gray-green1 circular spots called reduction halos 7fig4 #aj74 ,these spots1 which in places give the red shales a distinctive polka-dot appearance1 have been produced as the result of chemical change of certain minerals within the shale4 ,as noted earlier1 sediments are usually laid down in horizontal layers4 ,however1 in certain environments1 sediments may be deposited in such a way that the layers are inclined at angle to horizontal 7fig4 #aa74 ,this structure1 called cross-bedding or cross-stratification1 is found in certain sandstones and other coarse-grained or fragmental sedimentary rocks4 ,cross-bedding typically consists of rather distinct inclined layers separated by bedding planes 7the surface of demarcation between two individual rock layers74 ,bedding of this type commonly occurs in sedimentary rocks formed in rivers1 deltas1 and along the margins of lakes or oceans4 ,the cross-bedding in the ,quartermaster and certain of the ,triassic formations is believed to have been developed under similar conditions4 ,although cross-bedding is also common in certain rocks of eolian origin 7deposited by wind7 none of the cross-bedding in the canyon's rocks is due to the action of wind4 ,in addition1 some of the ,quartermaster strata have ripple marks on their surfaces4 ,these features are common in certain sedimentary rocks and were formed when the surface of a bed of sediment was agitated by waves or currents4 ,the size1 shape1 and cross section of the ripple marks can be used to tell whether the marks were produced by waves or currents4 ,the ripple marks in the ,quartermaster appear to have been formed by the action of waves on a shallow sea floor4 ,a number of interesting geologic features in the canyon have been formed in part in the ,quartermaster ,formation4 ,these include the multi-hued ,spanish ,skirts 7fig4 #bf71 the ,devil's ,slide 7fig4 #ce71 ,capitol ,peak 7fig4 #cb71 and ,catarina ,cave 7fig4 #bg74 ,the latter is a rather unusual cave in that it has developed in a large mass of landslide debris divided by projecting bedrock of the ,spanish ,skirts4 ,the cave has been formed by suffosian1 a process whereby water enters the landslide debris on the upper slopes and follows buried channels in the landslide removing rock debris as it passes through4 ,the flood water exits at the base of the landslide by means of ,catarina ,cave4 ,the plan of the cave closely resembles the drainage patterns of surface gullies4 ,tecovas ,formation4-- ,rocks of the ,triassic ,system 7fig4 #f7 are well represented in ,palo ,duro ,canyon and consist of the ,tecovas and ,trujillo ,formations4 ,these formations are part of the ,dockum ,group of ,late ,triassic age4 ,having a total thickness of about #bjj feet1 the ,tecovas 7which is named from exposures found on ,tecovas ,creek in ,potter ,county1 ,texas7 consists largely of multicolored shales4 ,also present are thin layers of soft sandstone1 which are disseminated throughout the shales1 and a more prominent bed of white sandstone1 which marks the middle of the formation4 ,the ,tecovas shales overlie the ,quartermaster ,formation1 and the lower zone of lavender1 gray1 and white shales forms a relatively smooth slope that is easily distinguished from the steeper slopes of gullied red-and-white-banded shales beneath them 7fig4 #ab74 ,illustration3 ,fig4 #aj4 ,chemical reactions in certain of the red ,quartermaster shales have produced reduction halos 7p4 #ai7 which give the rocks a polka-dot appearance4 ,illustration3 ,fig4 #aa4 ,this boulder1 located near the foot of ,triassic ,peak along the ,sad ,monkey ,railroad track1 exhibits the cross-bedding typical of the ,trujillo sandstones4 ,but the contact zone between the ,tecovas and ,quartermaster shales involves more than a mere change in color4 ,here is one of the missing 8chapters0 in the geologic history of the canyon1 for part of the ,late ,permian record and all of the record of ,early and ,middle ,triassic time are missing from the geologic column4 ,such gaps in the column are represented by unconformities in the rocks4 ,here the unconformity is an ancient erosional surface between the ,tecovas ,formation of ,late ,triassic age and the ,late ,permian ,quartermaster ,formation1 and there are many millions of years of earth history represented in this missing 8chapter0 in the geologic story of ,palo ,duro ,canyon4 ,during this vast span of time1 thousands of feet of sediments were probably deposited1 converted into rock1 and then later removed by erosion4 ,near the middle of the ,tecovas ,formation there is a bed of white1 crumbly 7friable7 sandstone4 ,averaging about #ae feet in thickness1 this sandstone contains many joints 7small crack-like fractures7 along which no appreciable movement has taken place 7fig4 #h74 ,there are two distinct sets of these joints which intersect each other at right angles4 ,the distinctive joint patterns1 the color1 and the friability of this sandstone clearly differentiate it from the harder1 darker1 and more coarse-grained sandstones of the overlying ,trujillo ,formation 7p4 #bb74 ,the upper part of the ,tecovas consists of a layer of orange shale which overlies the middle sandstone unit and is in contact with the lower part of the ,trujillo ,formation4 ,illustration3 ,fig4 #ab4 ,taken from the northwest rim near ,coronado ,lodge1 this photograph shows the four major rock units exposed in the park3 7#a7 ,the ,quartermaster ,formation which forms the lower wall and canyon floor2 7#b7 ,tecovas ,formation2 7#c7 ,trujillo ,formation which caps the mesas2 and 7#d7 ,ogallala ,formation4 ,the fossils which have been found in the ,tecovas ,formation suggest that these rocks were derived from sediments deposited in swamps and streams4 ,unlike the marine deposits of the ,quartermaster1 the rocks of the ,tecovas were formed from continental deposits laid down on the land4 ,fossils found in the canyon include the bones and teeth of the extinct semi-aquatic reptiles known as phytosaurs 7fig4 #ac7 and bone and skull fragments of a primitive amphibian called ,buettneria 7fig4 #ad74 ,coprolites 7the fossilized excrement of animals71 pieces of petrified wood1 and the teeth and bones of lungfish have also been reported from the ,tecovas4 ,illustration3 ,fig4 #ac4 ,the skull of this crocodile-like creature called a phytosaur is typical of the reptiles that inhabited the ,palo ,duro area during the ,triassic ,period4 7,photograph courtesy ,panhandle-,plains ,historical ,museum47 ,a number of minerals including hematite1 an iron mineral1 and psilomelane1 a barium-magnesium oxide1 occur in the ,tecovas4 ,hematite is an ore of iron and psilomelane a manganese ore1 though neither of these is present in commercial quantities in the canyon4 ,the ,tecovas also contains a number of concretions which range from a fraction of an inch to as much as #f inches in diameter4 ,these spherical masses are generally harder than the fine-grained shaly sands in which they are found and were thus left behind when the surrounding rock was eroded away4 ,some of these concretions are marked by cracks or veins filled with the mineral calcite4 ,concretions bearing this type of structure are called septaria1 or septarian concretions4 ,geodes are also found in the ,tecovas ,formation4 ,these are rounded concretionary rocks with a hollow interior that is frequently lined with mineral crystals4 ,well-formed crystals of clear calcite have been found in many of the geodes from the ,tecovas4 ,among park landmarks that are characterized by the multi-hued ,tecovas strata are the middle portion of ,triassic ,peak 7fig4 #be71 the upper part of the ,spanish ,skirts 7fig4 #bf71 ,capitol ,peak 7fig4 #cb71 and the ,devil's ,slide 7fig4 #ce74 ,trujillo ,formation4-- ,named from rock exposures on ,trujillo ,creek in ,oldham ,county1 ,texas1 the ,trujillo is easy to distinguish from the underlying ,tecovas ,formation4 ,the contact is quite distinct and lies between the top of the orange ,tecovas shale and the base of the massive-bedded1 cliff-forming ,trujillo sandstone 7fig4 #be74 ,although generally fine grained and thickly bedded1 there are local concentrations of pebble-sized rock fragments in the ,trujillo4 ,the weathered surface of the lower sandstone is stained red or dark brown by iron oxides4 ,however1 a fresh1 unweathered surface is typically gray or greenish gray in color1 and careful examination of the unweathered rock reveals the presence of tiny flakes of mica4 ,the basal ,trujillo sandstone is one of the most conspicuous rock units in the canyon and forms many of the prominent benches and mesas so typical of the ,palo ,duro landscape4 ,in places the sandstone is cross-bedded 7p4 #bj7 and contains channel deposits of coarse sand which suggest that the sediments from which it was derived were deposited in ancient stream beds4 ,red1 maroon1 and gray shales overlie the basal sandstone member of the ,trujillo1 and these shales are overlain by cross-bedded1 coarse-grained sandstone4 ,another interval of varicolored shales separates the middle sandstone bed from the upper sandstone member4 ,the middle sandstone unit is a conspicuous ledge- or cliff-forming rock and is medium to coarse grained and commonly cross-bedded4 ,in most localities1 the upper sandstone is overlain by a section of red and green shales which mark the uppermost limits of the ,trujillo ,formation4 ,in places1 however1 this shale section has been removed by erosion and rocks of ,tertiary age directly overlie the sandstone4 ,although fossils are not common1 the remains of ,buettneria 7fig4 #ad71 leaf imprints1 pieces of mineralized wood1 and the scattered teeth and bone fragments of reptiles and amphibians have been found4 ,phytosaur remains1 especially teeth1 have also been collected from the ,trujillo sandstones4 ,the ,indians who formerly inhabited the ,palo ,duro area 7p4 #c7 put the rocks of the canyon to a number of uses4 ,this appears to be especially true of the rather coarse-grained ,trujillo sandstones1 which were commonly used for constructing primitive rock shelters4 ,the abrasive surface of the sandstone was especially well suited for grinding grain1 and mortar holes have been found in a number of places4 ,one of these 7fig4 #ae7 can be seen along the tracks of the ,sad ,monkey ,railroad 7p4 #ce7 near the foot of ,triassic ,peak4 ,the ,indians also used the clays of the ,quartermaster1 ,tecovas1 and ,trujillo ,formations to make pottery1 and iron and copper minerals such as hematite and malachite were used to make red and green pigments for decoration and war paint4 ,the ,trujillo shales and sandstones can be seen in a number of ,palo ,duro's more spectacular geological oddities4 ,these erosional remnants are best developed where blocks of erosion-resistant sandstone protect underlying pedestals of softer shale 7fig4 #ae74 ,this type of differential weathering 7p4 #ca7 has produced a number of interesting and unusually shaped pedestal rocks or 8hoodoos0 7figs4 #af and #bj74 ,the most spectacular erosional remnant--and one that has come to be the 8trademark0 of ,palo ,duro ,canyon--is the ,lighthouse 7fig4 #ca74 ,the great jumble of boulders called the ,rock ,garden 7fig4 #cd7 is also composed largely of massive blocks of dislodged ,trujillo sandstone4 ,these boulders accumulated on the canyon floor as a result of landslides4 ,in addition1 the rock profile known as ,santana's ,face 7fig4 #bh7 is a naturally sculptured profile in the ,trujillo sandstone that forms the cap of ,timber ,mesa4 ,ogallala ,formation4-- ,the ,ogallala ,formation is named from exposures around ,ogallala in ,keith ,county1 ,nebraska4 ,there is a major unconformity between the ,trujillo ,formation of the ,triassic and the overlying ,ogallala ,formation of ,pliocene 7,late ,tertiary7 age4 ,missing here is the geologic evidence for what may have been some of the more exciting chapters in the canyon's history4 ,there is no record1 for example1 of the ,jurassic and ,cretaceous ,periods which together encompass almost #abj million years of earth history4 ,also missing is any evidence of what transpired during more than #ij percent of the ,tertiary ,period1 for no rocks of ,paleocene1 ,eocene1 ,oligocene1 or ,miocene age are exposed in the canyon4 ,together these four epochs comprise approximately #dg million years of earth history4 ,it is impossible1 of course1 to determine how many geologic formations may have been formed and later eroded during the #afg million years represented by this unconformity4 ,however1 our knowledge of present-day deposition and erosion suggests that the missing geologic record undoubtedly represents many thousands of feet of rock4 ,illustration3 ,fig4 #ad4 ,the skeleton of ,buettneria1 a large amphibian1 found in ,upper ,triassic strata in the canyon4 7,photograph courtesy ,panhandle-,plains ,historical ,museum47 ,the lower portion of the ,ogallala ,formation is composed of a reddish-brown1 fine- to medium-grained sandstone that contrasts sharply with the underlying red and green shales that are exposed in the top of the ,trujillo ,formation4 ,much of this sandy rock is characterized by pebbles consisting of a variety of igneous1 sedimentary1 and metamorphic rocks4 ,because it consists of rock and mineral fragments of varied composition and size1 this kind of sedimentary rock is called a conglomerate4 ,the type of rock fragments found in basal ,ogallala conglomerates suggests that they were transported to the ,panhandle-,plains area by streams flowing southeastward from the ,rocky ,mountains4 ,as these streams deposited their loads1 they left behind a wide spread blanket of sand1 gravel1 and mud which formed an extensive alluvial plain that extended from western ,nebraska to northwest ,texas4 ,although it is less than #ajj feet thick in ,palo ,duro ,canyon1 in places this great mantle of fluvial 7stream-deposited7 sediments is as much as #ijj feet thick4 ,illustration3 ,fig4 #ae4 ,the depression in this boulder is a mortar hole believed to have been used by the ,indians for grinding corn4 ,illustration3 ,fig4 #af4 ,this pedestal rock1 located near the ,lighthouse1 is capped by a slab of weather-resistant ,trujillo sandstone4 ,most of the ,ogallala ,formation consists of a mixture of diverse rock types such as conglomerate1 sandstone1 siltstone1 clay and marl4 ,but the upper part of the formation is characterized by thick caliche deposits4 ,a dull1 earthy calcite deposit1 caliche typically forms in areas of scant rainfall4 ,it is believed to originate when ground moisture1 containing dissolved calcium bicarbonate1 moves to the surface where the moisture steadily evaporates leaving a calcium carbonate crust on or near the surface 7fig4 #ag74 ,caliche1 which derives its name from the ,latin calix1 meaning 8lime10 may be firm and compact or loose and powdery4 ,it is also commonly found mixed with other materials such as clay1 sand1 or gravel4 ,caliche commonly occurs in the ,trans-,pecos1 southwestern ,gulf ,coastal ,plain1 and the ,high ,plains area of ,texas 7see fig4 #e1 p4 #h74 ,in the latter area it typically makes up the 8caprock40 ,caliche is commonly quarried in these parts of ,texas where it is used as road material and as an aggregate4 ,good exposures of ,ogallala caliche can be seen on the surface around the overlook at ,coronado ,lodge on the northwest rim of the canyon 7fig4 #ag74 ,ogallala strata also crop out along the upper reaches of ,park ,road #e as it starts to descend into the canyon4 ,but probably the most spectacular exposures of the ,ogallala are exposed in the precipitous face of the ,fortress ,cliff 7fig4 #cc7 which forms part of the eastern rim of the canyon4 ,also located within the ,ogallala ,formation is a very important aquifer--a porous1 water-bearing rock formation4 ,this fine-to coarse-grained sandstone is very porous and permeable and is the most important single water-producing formation in the ,panhandle-,plains area4 ,illustration3 ,fig4 #ag4 ,the white surface in the right foreground consists of caliche 7p4 #bf7 in the ,ogallala ,formation4 ,coronado ,lodge can be seen in the right background4 ,opal and chert are locally abundant in the ,ogallala conglomerates4 ,the opal1 which is found in small cavities in the conglomerate is not of the gem variety but it does fluoresce4 ,minerals that exhibit fluorescence emit visible colors when exposed to ultraviolet light4 ,for this reason1 the ,ogallala opal is sought after by rock and mineral collectors4 ,the chert1 a flint-like variety of quartz1 occurs as nodules in the conglomerate and in a well-developed layer near the base of the formation4 ,both of these siliceous 7silica-bearing7 rocks were apparently prized by the ,indians1 who used them to fashion knives1 scrapers1 projectile points1 and other artifacts4 ,the ,indians also learned that flat slabs of caliche were ideal for lining fireplaces and to construct primitive rock shelters4 ,a number of ,pliocene vertebrates have been found in the ,palo ,duro area4 ,known as the 8,age of ,mammals10 the ,tertiary ,period was characterized by mammals as diverse as were the reptiles of the ,mesozoic ,era4 ,among these unusual creatures were such now-extinct species as the saber-tooth cat and the elephant-like shovel-jawed mastodon 7fig4 #ah74 ,the remains of these as well as bones of giraffe-like camels1 pony-sized horses1 and sloths have been found in the vicinity of the canyon4 ,the grassy plains of ,pliocene time were also inhabited by large tortoises which reached lengths of up to #c feet 7fig4 #ai74 ,dioramas showing how these animals might have looked1 as well as their actual remains1 are on display in the ,hall of ,pre-,history in the lower floor of the ,panhandle-,plains ,historical ,museum in ,canyon1 #ac miles west of the park 7p4 #ce74 ,illustration3 ,fig4 #ah4 ,this life-size model of a shovel-jawed mastodon is typical of the now-extinct1 elephant-like creatures that lived in this area during the ,pliocene ,epoch4 7,photograph courtesy ,panhandle-,plains ,historical ,museum47 ,illustration3 ,fig4 #ai4 ,the carapaces of giant tortoises as much as #c feet long have been collected from ,pliocene rocks in the ,palo ,duro area4 7,photograph courtesy ,panhandle-,plains ,historical ,museum47 ,rocks of the ,pleistocene4-- ,the youngest rocks in ,palo ,duro ,canyon ,state ,park were formed during the ,pleistocene ,epoch of the ,quaternary ,period of the ,cenozoic ,era 7see geologic time scale1 p4 #aa74 ,pleistocene rocks are rather widespread in much of the ,panhandle-,plains area and they are mostly composed of sediments which were deposited in stream valleys1 in lakes or ponds1 or by the wind4 ,most of the ,pleistocene strata in the park area consist of loose deposits of silt and sand which were deposited by wind action4 ,known locally as 8blow sand10 this reddish-brown1 silty sand overlies the ,ogallala caliche at most points along the canyon's rim4 ,,how ,,the ,,canyon ,,was ,,carved ,the visitor seeing ,palo ,duro ,canyon for the first time may find it difficult to believe that this yawning chasm began as a simple gully4 ,but to the geomorphologist--the geologist who studies the origin and development of landscapes--,palo ,duro ,canyon is but a gully magnified many times over4 ,this is evident because the shape of the canyon1 the nature of its tributaries1 and the character of its walls indicate that it has been deepened and lengthened by the downcutting of a stream and widened by other geologic processes4 ,,the ,,geologic ,,work ,,of ,,running ,,water ,palo ,duro ,canyon is a classic example of a land-form that has been created by the geologic work of running water4 ,undoubtedly the most important single agent of erosion1 running water probably does more to wear away the land than all the other geologic agents combined4 ,this is not surprising considering the fact that the earth's annual precipitation 7such as rain and snow7 equals about four billion tons of water4 ,although the amount of precipitation varies greatly from place to place1 the average annual precipitation on land is about #dj inches of water4 ,of this1 roughly #be percent runs off from the land to form streams4 ,when one drives through the park and fords the normally gently flowing waters of the ,prairie ,dog ,town ,fork of the ,red ,river he may well wonder if this unimposing stream actually is the geologic agent that is responsible for this deep gorge4 ,but the visitor who happens to be present during a severe rainstorm will soon be convinced1 for during heavy rains this gentle stream becomes a raging torrent4 ,as the river increases in size it also becomes a more effective land-shaping tool1 for the larger and swifter the stream1 the more rock material it can carry4 ,thus1 when flowing at peak capacity1 this branch of the ,red ,river becomes a moving ribbon of sandpaper whose load of sand1 silt1 and gravel has cut and scoured the canyon walls and floor for hundreds of thousands of years4 ,how long has it taken the river to carve this remarkable chasm8 ,although there is no way of knowing for sure1 geologic evidence indicates that the canyon has formed during the last one million years--a relatively short time1 geologically speaking4 ,the work of the river is made still more effective by water and sediment which it receives from its tributaries2 this added water substantially increases the volume and velocity of the river4 ,although many of the tributary streams are dry throughout much of the year1 they carry large quantities of water during heavy rains4 ,moreover1 because most of these streams flow over rock surfaces which are not protected by thick soil or vegetation1 their waters are quickly transported to the master stream4 ,thus1 the volume and velocity of the ,prairie ,dog ,town ,fork of the ,red ,river make it possible--especially during flood periods--for the river to carry a large load of rock particles which effectively erodes the stream channel4 ,where does this rock debris come from8 ,most of it is eroded from the sides and bottom of the river's channel4 ,the river carries its load in a number of ways4 ,material such as salt and other soluble matter is transported in a dissolved state or in solution4 ,still more1 for example1 silt and fine sand1 is carried in suspension4 ,these sediments are suspended between the surface of the water and the bottom of the stream channel4 ,those particles that will not dissolve in water and are too heavy to be carried in suspension1 constitute the bottom load of the stream4 ,these larger sediments1 such as gravel1 cobbles1 and boulders1 roll1 bounce1 or slide along the stream bed4 ,as flash floods course through ,palo ,duro ,canyon1 the river uses its load to erode further the rocks over which it passes4 ,each moving rock fragment literally becomes a cutting tool for abrasion as the loose rock particles slowly wear away the banks and bed of the stream4 ,eventually the abraded rock fragments become smooth and rounded and the stream channel is gradually worn down to a lower level2 it is also widened4 ,the river also erodes by hydraulic action as loose rock fragments are lifted and moved by the force of the stream's current4 ,this process is similar to the effect produced when soil is churned up and washed away when water from a garden hose is sprayed on loose earth4 ,the effects of hydraulic action have played an important role in widening the canyon1 for recession of the cliffs away from the middle of the canyons has been caused in part by undercutting4 ,thus1 as the soft shale and gypsum beds were removed by the stream1 the overlying sandstone formations gradually broke off and fell into the canyon4 ,once on the canyon floor1 most of the slabs and blocks of sandstone were eventually broken up and carried away by the streams as sand and mud4 ,not all of the boulders have been destroyed in this manner2 in places 7for example1 the ,rock ,garden7 similar boulders are seen today 7fig4 #cd74 ,,weathering ,,and ,,gravity ,,add ,,the ,,final ,,touch ,most of the energy of the river has been expended in downcutting1 for the canyon has apparently been deepened more rapidly than it has been widened4 ,but as the stream gouged its channel deeper into the bedrock1 an ever-increasing expanse of canyon wall was exposed to other agents of erosion4 ,slowly--almost imperceptibly--the walls of the canyon have been eroded by the processes of weathering and mass-wasting4 ,weathering4-- ,wherever rocks are exposed on the earth's surface1 they are attacked by the agents of weathering4 ,they are dissolved by rainwater1 pried apart by frost and ice1 and blasted by windblown sand4 ,some of the changes produced by weathering are purely mechanical1 that is1 the rock is simply reduced to smaller fragments without being broken down chemically or undergoing any change in its mineral composition4 ,this mechanical weathering1 or disintegration1 takes place in a number of ways4 ,changes are especially noticeable in rocks that are subjected to large daily temperature variations4 ,if a crack in these rocks becomes filled with water and the temperature drops below freezing1 ice forms4 ,when water freezes it expands by about #aj percent of its volume--this is the reason why water pipes often split open during the winter4 ,just as in a water pipe1 the pressure of the expanding ice is commonly great enough to widen and deepen the crack in the rock4 ,this process1 called frost wedging1 may ultimately cause the rock to split and fall apart4 ,the cumulative effects of frost wedging have probably played a significant role in prying off large blocks of rocks from the walls and rim of the canyon4 ,animals and plants may also hasten rock disintegration4 ,plant roots commonly grow in rock crevices and as the roots become larger they wedge the rock apart4 ,burrowing animals such as rabbits1 gophers1 and ground squirrels also promote rock disintegration4 ,although they do not attack the rocks directly1 their digging exposes new rock surfaces to weathering processes4 ,the holes these creatures make also permit water and air to enter the earth more easily1 thereby hastening rock destruction4 ,man1 of course1 promotes more rock disintegration than all other animals combined4 ,thus1 as one explores the canyon's trails and climbs its walls1 he will not only see evidence of the various types of mechanical weathering1 he will also be contributing to the further wearing away of the rocks4 ,decomposition1 or chemical weathering1 works hand in hand with mechanical weathering4 ,but unlike disintegration1 decomposition produces rock materials that are basically different from the original unweathered rock4 ,these changes are brought about as the result of chemical reactions between minerals in the rocks and water1 carbon dioxide1 and oxygen4 ,although the arid climate and severe winters of the ,panhandle generally facilitate mechanical weathering1 some of the red shales and gypsum deposits show the effect of oxidation1 hydration1 and other forms of chemical weathering 7fig4 #aj74 ,mass-wasting4-- ,mass-wasting1 the erosional process by which rock and soil move downslope in response to the force of gravity1 has also been instrumental in shaping ,palo ,duro ,canyon4 ,this type of erosion has been especially active on the walls of the canyon1 for here the slopes are steep enough to promote downward movement of earth materials4 ,in a few places there have been landslides which have moved large quantities of rock in a short span of time4 ,but most mass movements have been imperceptibly slow as masses of talus 7accumulations of rock debris7 on steeper slopes have inched slowly downhill because of their own weight4 ,talus deposits produced in this way can be seen at the foot of most of the cliffs and erosional remnants throughout the canyon 7fig4 #bj74 ,differential erosion4-- ,even the most casual observer will soon note that not all of the canyon's rocks have been equally affected by erosion4 ,indeed1 it is the nature of this differential erosion that gives ,palo ,duro ,canyon the rugged sculptured appearance that accounts for much of its beauty4 ,visitors to ,palo ,duro ,canyon commonly ask why the rock formations are so diversely shaped4 ,the answer to this question lies in the rocks themselves4 ,because the various rock strata are of unequal hardness1 they erode at different rates of speed4 ,hence1 the harder1 more resistant rocks1 such as the sandstones and conglomerates of the ,trujillo ,formation1 form the shelves1 ledges1 and 8caps0 of the rock sculptures4 ,the ,lighthouse 7fig4 #ca7 and other pedestal rocks 7fig4 #af7 are good examples of land-forms produced by differential erosion4 ,the 8hoodoos0 mentioned earlier are also the products of this type of erosion 7figs4 #af and #bj74 ,illustration3 ,fig4 #bj4 ,talus slopes 7arrow7 are well developed on the east side of ,capitol ,peak and in places obscure the ,quartermaster red beds4 ,note the 8hoodoo0 at the south 7left7 end of the structure4 ,softer rocks like shales and clay are more readily eroded and they normally form slopes rather than cliffs or ledges 7fig4 #ab74 ,grooves1 recesses1 and caves have also developed in some of the less resistant rocks such as the shales and gypsum beds of the ,quartermaster ,formation4 ,catarina ,cave 7fig4 #bg7 which has formed in the red and white shales of the ,spanish ,skirts 7fig4 #bf7 is a good example of this type of feature4 ,caves of this type afforded protection to both man and wild animals since the dawn of history1 for their remains have been found in a number of similar caves4 ,thus1 within a relatively short time--geologically speaking--the familiar land-shaping processes described above have joined forces to provide ,texas with one of its most remarkable natural attractions4 ,but interestingly enough1 the same geologic processes that created these unusual formations are busily at work destroying them4 ,as time passes and erosion progresses1 the caps of the pedestals are worn away and the underlying shales crumble and are washed into the valley below4 ,yet even as the old land-forms are being destroyed1 wind1 water1 ice1 and man are attacking the canyon walls to produce still more of these interesting erosional remnants4 ,,what ,,to ,,do ,,and ,,see ,,at ,,palo ,,duro ,,canyon ,,state ,,park ,the visitor to ,palo ,duro ,canyon can choose from a number of recreational and educational activities4 ,moreover1 regardless of whether one visits for a few hours to picnic along the banks of the river1 or spends a week at one of the well-kept campgrounds1 the visit will probably be both pleasant and rewarding4 ,in the pages that follow there is a brief description of certain of the park landmarks and some of the more popular attractions within the canyon4 ,the numbers in parentheses refer to numbers which designate these places on the map of ,palo ,duro ,canyon 7fig4 #b1 pp4 #d-e74 ,hopefully1 this information will help one to plan his visit to the canyon and thereby make his stay more enjoyable and worthwhile4 ,park ,entrance 7#a74-- ,the first stop in the park is the gate at the ranger station 7fig4 #ba74 ,here one pays a modest admission fee and receives literature and information about the park4 ,the park is open every day of the year1 but the entrance gates close at sundown4 ,coronado ,lodge and ,observation ,point 7#b74-- ,the overlook at ,coronado ,lodge 7fig4 #bb71 located about half a mile from the ,park ,entrance1 is a good place to start one's visit4 ,situated on a ledge of ,ogallala caliche 7p4 #bf71 the ,lodge is an attractive1 rustic structure constructed of blocks of ,trujillo sandstone 7p4 #bb74 ,its picture windows and outdoor overlook provide a matchless view of the canyon and make it possible to become oriented for the descent to the canyon floor4 ,large1 coin-operated telescopes permit close-up views of distant parts of the canyon1 and there are museum cases containing objects of historical and geological interest from the ,palo ,duro area4 ,if possible one should visit the ,coronado ,observation ,point more than once during the visit1 preferably at different times of the day4 ,because of shifting clouds and changing lighting conditions1 the canyon presents a continually changing panorama from sunrise to sunset4 ,open year-round1 the ,lodge offers a complete line of souvenirs1 film1 and camping supplies4 ,there is also a snack bar where coffee1 sandwiches1 and cold drinks can be purchased4 ,the ,scenic ,drive 7#a-af74-- ,after viewing the canyon from ,coronado ,lodge1 one should take the scenic drive on ,park ,road #e4 ,this paved1 all-weather road descends the northwest rim of the canyon and continues on to the turnaround at ,cow ,camp1 a distance of about #h miles4 ,although the present scenic drive was completed in #aiea1 the path that it follows is essentially that which was laid out by ,colonel ,charles ,goodnight when he established ,palo ,duro ranch in #ahgf4 ,the road descends to the canyon floor in a series of well-engineered turns1 but because it drops some #hjj feet in little more than a mile it is wise to use second or low gear on the descent4 ,one should also observe the posted speed limits 7#aj to #bj miles per hour7 and keep to the right side of the road at all times4 ,in the #hjj-;foot drop from rim to floor1 the complete geologic section of the canyon is traversed1 as one passes from the ,pleistocene sands through the ,ogallala1 ,trujillo1 and ,tecovas ,formations1 before reaching the ,quartermaster ,formation which is exposed in the canyon floor4 ,each of these geologic formations is discussed elsewhere in this publication 7pp4 #af-bh74 ,pioneer ,amphitheatre 7#c74-- ,upon reaching the canyon floor1 ,park ,road #e flattens out and from this point it is but a short distance to the ,pioneer ,amphitheatre1 one of the canyon's newest and most popular attractions4 ,here1 located at the foot of a colorful #fjj-;foot cliff1 is a remarkable #aejj-seat outdoor theatre of latest design 7fig4 #bc74 ,each evening during a ten-week summer season1 a symphonic drama portraying the history of the ,texas ,panhandle is presented in the amphitheatre4 ,information about these productions can be obtained at the ,park ,entrance1 ,coronado ,lodge1 and other points within the park4 ,illustration3 ,fig4 #ba4 ,the entrance gate to ,palo ,duro ,canyon ,state ,park4 ,illustration3 ,fig4 #bb4 ,coronado ,lodge on the canyon's northwest rim affords panoramic views of the canyon4 ,sad ,monkey ,train ,ride 7#d74-- ,the ,sad ,monkey ,railroad begins--and ends--at ,sad ,monkey1 ,texas1 a small 8community0 that lies at the foot of ,triassic ,peak 7fig4 #bd74 ,unlike most miniature railroads1 the ,sad ,monkey ,special is not a 8kiddie0 ride4 ,instead1 this #b-mile journey provides an opportunity to get away from the road for a closer look at the geologic formations exposed along the track4 ,there are especially good views of the ,spanish ,skirts 7fig4 #bf71 ,catarina ,cave 7fig4 #bg71 and ,triassic ,peak 7fig4 #be74 ,these1 and other features of geologic interest1 are pointed out by an experienced lecturer who also presents a brief review of the geologic history of the area4 ,triassic ,peak 7#e74-- ,long used by ,indians and ranchers as a ,palo ,duro landmark1 the canyon visitor will find ,triassic ,peak to be equally useful as a geologic landmark4 ,when viewed from the ,sad ,monkey ,railroad ,terminal1 the south face of ,triassic ,peak clearly reveals three of the four major geologic formations of the canyon 7fig4 #be74 ,illustration3 ,fig4 #bc4 ,located on the canyon floor1 ,pioneer ,amphitheatre is a modern outdoor theatre where symphonic dramas are presented each summer4 7,courtesy ,mrs4 ,ples ,harper1 ,texas ,panhandle ,heritage ,foundation1 ,inc42 photograph by ,ron ,horn47 ,the lower one-third of the peak consists of deeply furrowed1 red and white banded shales of the ,quartermaster ,formation 7p4 #ag74 ,overlying the ,permian red beds are the brightly colored1 multi-hued ,tecovas shales of ,triassic age 7p4 #ai74 ,the composition of the ,tecovas is such that the lower shales tend to weather into relatively gentle slopes with rather smooth surfaces4 ,triassic ,peak is capped by a weather-resistant layer of ,trujillo sandstone1 and this durable cliff-forming sandstone has served as a protective covering to impede the erosion of the softer rocks of the ,tecovas and ,quartermaster ,formations4 ,although it has withstood the ravages of time exceedingly well1 the large blocks of ,trujillo sandstone which litter the flanks and foot of ,triassic ,peak clearly indicate that weathering and mass-wasting have exacted their toll in the geologic past4 ,illustration3 ,fig4 #bd4 ,a trip on the ,sad ,monkey ,railroad is a good place to learn more about the canyon's geology and get a closer look at the rocks4 ,illustration3 ,fig4 #be4 ,excellent exposures of the ,quartermaster ,formation of ,permian age 7#a7 and the ,triassic ,tecovas 7#b7 and ,trujillo 7#c7 ,formations can be seen in the south face of ,triassic ,peak4 ,the feature known as the ,sad ,monkey is indicated by the arrow4 ,sad ,monkey1 ,texas derives its name from the prominent mass of ,trujillo sandstone at the southern extremity of ,triassic ,peak4 ,when viewed in the proper perspective--and with the proper amount of imagination--this massive block of sandstone bears a striking resemblance to an aged and saddened monkey4 ,spanish ,skirts 7#f74-- ,few of the canyon's features are as well-named as the gaudy ,spanish ,skirts 7fig4 #bf74 ,the lower part of this multi-colored bluff consists of alternating layers of red and white ,quartermaster shale1 capped by the colorful maroon and lavender ,tecovas shales4 ,located on the north flank of ,timber ,mesa1 the ,spanish ,skirts and nearby ,catarina ,cave can be reached by an easy half-mile path4 ,the trail begins on the west side of ,park ,road #e1 just beyond the ,timber ,creek bridge located several hundred feet from the ,sad ,monkey ,station4 ,catarina ,cave 7#g74-- ,a short distance west of the ,spanish ,skirts lies ,catarina ,cave4 ,this depression has been washed out of the relatively soluble ,permian shales 7fig4 #bg74 ,santana's ,face 7#h74-- ,like ,triassic ,peak1 ,timber ,mesa is capped by a thick layer of massively bedded ,trujillo sandstone4 ,on the eastern tip of the mesa the sandstone has been eroded in such a fashion that it resembles the profile of an ,indian 7fig4 #bh74 ,this feature1 called ,santana's ,face1 is best seen from the park road shortly after leaving ,sad ,monkey ,station4 ,illustration3 ,fig4 #bf4 ,the gaudy ,spanish ,skirts are a colorful expanse of ,quartermaster and ,tecovas strata exposed on the north flank of ,timber ,mesa4 ,note the contrast in weathering in the lower1 gullied ,quartermaster ,formation and the smooth slopes of the ,tecovas shales above it4 ,catarina ,cave 7arrow7 is at the right4 ,the ,sky ,ride 7#i74-- ,the ,sky ,ride1 located near the first water crossing on ,park ,road #e1 transports visitors from the canyon floor to the top of ,timber ,mesa 7fig4 #bh74 ,the #cjj-;foot ascent is made in ski-lift chairs that are comfortable and safe4 ,the observation area atop the mesa offers an unusually fine view of most parts of the canyon4 ,illustration3 ,fig4 #bg4 ,catarina ,cave 7arrow7 is easily reached by a half-mile trail from ,park ,road #e4 ,illustration3 ,fig4 #bh4 ,santana's ,face 7left arrow7 has been sculptured from the ,trujillo sandstone cap of ,timber ,mesa4 ,the cable for the ,sky ,ride 7p4 #cg7 passes through the notch indicated by arrow at right4 ,the ,first ,water ,crossing 7#aj74-- ,as it winds through the canyon1 the park road crosses the ,prairie ,dog ,town ,fork of the ,red ,river seven times in a distance of about #d miles4 ,these fords1 or water crossings as they are called locally1 are paved and are normally safe to pass through4 ,they should1 however1 be avoided during times of heavy rains and flash flooding4 ,because of stream erosion1 especially fine exposures of the ,quartermaster ,formation are revealed in the stream banks near several of the crossings4 ,the first of these crossings 7fig4 #bi7 is about #a mile from the ,sad ,monkey ,station and is one of the more popular picnic areas in the park4 ,this area was also popular with earlier residents of the park1 for it is believed to have been the campgrounds of both the ,kiowa and ,comanche ,indians4 ,colonel ,charles ,goodnight's ,dugout 7#aa74-- ,as mentioned earlier 7p4 #f7 ,colonel ,charles ,goodnight entered the canyon in #ahgf with more than #af1jjj head of cattle4 ,although he later established more comfortable quarters1 ,col4 ,goodnight first lived in a primitive dugout similar to the one shown in figure #cj4 ,a replica of this early shelter has been constructed of mud1 stone1 and logs and can be seen on the west side of the park road just beyond the first water crossing 7see fig4 #bi74 ,illustration3 ,fig4 #bi4 ,now a popular picnic spot1 the wooded area near the first water crossing through the ,prairie ,dog ,town ,fork of the ,red ,river was a favorite ,indian campground4 ,the ,lighthouse 7#ab74-- ,the unpaved road to the ,lighthouse enters ,park ,road #e about two-tenths of a mile beyond the first water crossing4 ,although considered by many to be the canyon's best-known landmark1 the ,lighthouse is actually not within park boundaries4 ,it is located in ,little ,sunday ,canyon about #c miles west of the road and is not easily accessible to the average visitor4 ,like many of the park's natural attractions1 the ,lighthouse is an erosional remnant of colorful ,trujillo shales and sandstones 7fig4 #ca74 ,a similar pedestal rock1 the ,devil's ,tombstone1 can be reached by means of a trail which leaves the ,lighthouse road and enters ,sunday ,canyon4 ,illustration3 ,fig4 #cj4 ,when ,colonel ,charles ,goodnight settled in the canyon in #ahgf he lived in a primitive dugout similar to the one shown here4 ,capitol ,peak 7#ac74-- ,capitol ,peak 7figs4 #bj and #cb7 is a rather imposing geologic feature that can be seen from a number of points along ,park ,road #e4 ,there are especially good views in the vicinity of the second water crossing if one will look to the west of the road4 ,just beyond the crossing an unimproved road leads to the foot of ,capitol ,peak4 ,the lower part of this feature is composed of ,quartermaster shales of ,permian age and the upper section consists largely of ,triassic ,tecovas shales4 ,when viewed from the proper angle1 the silhouette of ,capitol ,peak is thought to resemble the prostrate form of a human 7fig4 #cb74 ,for this reason it has also been called the ,sleeping ,indian4 ,fortress ,cliff 7#ad74-- ,the ,ogallala ,formation of ,pliocene age 7p4 #bc7 forms the upper rim of the canyon and is well exposed in impressive ,fortress ,cliff 7fig4 #cc74 ,although this precipitous cliff dominates the eastern rim of the canyon along most of the scenic drive1 especially good views are afforded between the second and third water crossings4 ,the ,rock ,garden 7#ae74-- ,shortly after fording the river at the fifth water crossing1 there is a jumbled pile of boulders on the west side of the road 7fig4 #cd74 ,this accumulation of ,trujillo sandstone blocks has been named the ,rock ,garden4 ,many boulders such as these have accumulated on the floor of the canyon in ages past4 ,however1 most of these have been destroyed by weathering and their fragments removed by the canyon's streams4 ,the ,devil's ,slide 7#af74-- ,the ,devil's ,slide can be reached by an unimproved road that leads southwest from the scenic drive for a distance of about half a mile4 ,composed of upper ,quartermaster and lower ,tecovas shales1 the surface of this eroded spur is laced with many trails and 8slides0 that have been made by previous visitors 7fig4 #ce74 ,illustration3 ,fig4 #ca4 ,the ,lighthouse1 an erosional remnant and the 8trademark0 of ,palo ,duro ,canyon1 exhibits well the geologic phenomenon of differential erosion 7p4 #ca74 ,the ,turnaround 7#ag74-- ,a loop marks the end of ,park ,road #e and the conclusion of the scenic drive4 ,located in this area are a number of fine camping areas1 picnic grounds1 the old stone cottages called the 8,cow ,cabins10 and rest rooms with shower facilities 7fig4 #cf74 ,illustration3 ,fig4 #cb4 ,the 8dome0 on ,capitol ,peak is a well-known canyon landmark4 ,composed of the ,tecovas and ,quartermaster ,formations1 the profile of ,capitol ,peak is referred to as the ,sleeping ,indian4 7,the 8,indian's0 head can be seen in the right background47 ,illustration3 ,fig4 #cc4 ,fortress ,cliff is a prominent feature on the eastern rim of the canyon4 ,seen here are the precipitous cliffs developed in the ,ogallala caliche 7p4 #bf7 and the sandstones and shales of the ,trujillo ,formation4 ,illustration3 ,fig4 #cd4 ,the ,rock ,garden is a jumbled mass of ,trujillo sandstone boulders that mark the site of an ancient landslide4 ,hiking4-- ,there are a number of established trails for the visitor who is interested in hiking4 ,the more popular trails include those to the ,spanish ,skirts and ,catarina ,cave 7p4 #cg71 the ,devil's ,tombstone1 the ,lighthouse 7p4 #ci71 and the ,devil's ,slide 7p4 #dj74 ,park rangers will be glad to provide more complete information about these and other trails within the canyon4 ,horseback riding4-- ,saddle horses can be rented at the stables located east of the road near the ,pioneer ,amphitheatre4 ,there are a number of trail rides that can be taken on well-trained horses accustomed to the rugged terrain of the canyon4 ,additional information may be obtained from the attendants at the stable4 ,camping and picnicking4-- ,an ample number of well-developed camping and picnic areas are scattered throughout the canyon4 ,most are located adjacent to or a short distance from ,park ,road #e2 they are equipped with outdoor fireplaces and tables4 ,running water1 rest rooms1 and showers are provided in certain areas4 ,campsites are available on a first-come first-served basis1 and there is a #aj-;day limit on overnight camping4 ,detailed information on camping regulations and camping areas is available from a park ranger or at the ,entrance ,station4 ,photography4-- ,palo ,duro ,canyon offers many opportunities for both amateur and professional photography4 ,the multi-colored rock formations1 erosional land-forms1 and plants and animals offer limitless possibilities to the creative and imaginative photographer4 ,color shots are especially effective1 but a haze filter will be helpful when photographing distant objects4 ,morning and afternoon are the best times for picture taking as the mid-day sun is 8flat0 and lends little perspective to the canyon scene4 ,illustration3 ,fig4 #ce4 ,the ,devil's ,slide in the south end of the park is an eroded spur of ,tecovas shales4 ,some of the 8slides0 made by visitors are indicated by the arrow4 ,illustration3 ,fig4 #cf4 ,outcrops of the ,quartermaster 7#a7 and ,tecovas 7#b7 ,formations provide a geological backdrop for this campsite near the turnaround at the end of ,park ,road #e4 ,,panhandle-,,plains ,,historical ,,museum ,illustration3 ,fig4 #cg4 ,located on the campus of ,west ,texas ,state ,university in ,canyon1 the ,panhandle-,plains ,historical ,museum has many exhibits of historical and geological interest that will enhance one's visit to ,palo ,duro ,canyon ,state ,park4 7,courtesy ,panhandle-,plains ,historical ,museum47 ,the visitor to ,palo ,duro ,canyon ,state ,park would do well to start his visit at the ,panhandle-,plains ,historical ,museum located on the campus of ,west ,texas ,state ,university in ,canyon 7fig4 #cg74 ,here all phases of history--recent1 archeologic1 and geologic--are depicted in the various halls4 ,in the ,hall of ,pre-,history are the fossilized remains and reconstructions of ancient animals that were entombed in the canyon walls as long as #bjj million years ago4 ,elsewhere there are exhibits and dioramas that portray human history in the ,palo ,duro area4 ,beginning with the oldest known evidence of human occupation about #ab1jjj years ago1 there is a succession of displays that tell the story of man in the ,palo ,duro--,high ,plains region4 ,these exhibits follow man from the early ,indians living in stone shelters1 to the horse-using nomadic plains ,indians who relied heavily on the great herds of bison and who fought a desperate but losing battle to save their homeland from invasion by the white man4 ,here1 too1 is the story of the coming of the ,spanish conquistadores1 the comancheros 7see p4 #f71 and the advent of the anglican settler4 ,all are portrayed by means of artifacts that represent the different cultures of the region's colorful past4 ,the major theme of the ,museum is the history of the ,high ,plains during the period of the cattle industry of the open range4 ,one entire hall is devoted to the display of saddles1 spurs1 lariats1 barbed wire1 branding irons1 a chuck wagon1 and a life size model of a typical cowboy of the ,old ,west4 ,the ,museum also houses one of the nation's finest collections of guns of the ,old ,west1 the ,old ,world1 and guns of today4 ,other highlights include scale models depicting scenes of the ,old ,west1 exhibits of typical rooms from pioneer homes furnished with furniture of that era1 a fine assortment of antique vehicles1 and famous collections of ,western art4 ,the ,panhandle-,plains ,historical ,museum is easily reached from any of the major highways that pass through ,canyon4 ,it is open from #i3jj a4m4 to #e3jj p4m4 weekdays and from #b3jj p4m4 to #f3jj p4m4 ,sundays4 ,,selected ,,references#b ,brand1 ,j4 ,p4 7#aief7 ,triassic ,system1 in ,eastern ,llano ,estacado and adjoining ,osage ,plains3 ,west ,texas ,geol4 ,soc4 and ,lubbock ,geol4 ,soc41 ,guidebook1 ,spring ,field ,trip1 ,april #f-g1 #aief1 pp4 #h-i4 ,cummins1 ,w4 ,f4 7#ahij7 ,the ,permian of ,texas and its overlying beds3 ,texas ,geol4 ,survey #ast ,ann4 ,rept4 7#ahhi71 pp4 #ahc-aig4 ---- 7#ahic7 ,notes on the geology of northwestern ,texas3 ,texas ,geol4 ,survey #dth ,ann4 ,rept4 7#ahib71 pt4 #a1 pp4 #agg-bch4 ,drake1 ,n4 ,f4 7#ahib7 ,stratigraphy of the ,triassic formations of northeast ,texas3 ,texas ,geol4 ,survey #crd ,ann4 ,rept4 7#ahia71 pp4 #bbe-bdg4 ,evans1 ,g4 ,l4 7#aidi7 ,upper ,cenozoic of the ,high ,plains3 ,west ,texas ,geol4 ,soc4 and ,new ,mexico ,geol4 ,soc41 ,guidebook for ,field ,trip ,no4 #b1 ,november #i1 #aidi1 pp4 #a-i4 99----1 and ,meade1 ,g4 ,e4 7#aide7 ,quaternary of the ,texas ,high ,plains1 in ,contributions to ,geology1 #aidd3 ,univ4 ,texas ,pub4 #ddja1 pp4 #dhe-ejg4 99,frye1 ,j4 ,c41 and ,leonard1 ,a4 ,b4 7#aieg7 ,studies of ,cenozoic geology along eastern margin of ,texas ,high ,plains1 ,armstrong to ,howard counties3 ,univ4 ,texas1 ,bur4 ,econ4 ,geol4 ,rept4 ,inves4 ,no4 #cb1 #fb pp4 99----1 and ---- 7#aiei7 ,correlation of the ,ogallala ,formation 7,neogene7 in western ,texas with type localities in ,nebraska3 ,univ4 ,texas1 ,bur4 ,econ4 ,geol4 ,rept4 ,inves4 ,no4 #ci1 #df pp4 99----1 and ---- 7#aifd7 ,relation of ,ogallala ,formation to the southern ,high ,plains in ,texas3 ,univ4 ,texas1 ,bur4 ,econ4 ,geol4 ,rept4 ,inves4 ,no4 #ea1 #be pp4 99,girard1 ,r4 ,m4 7#aiei7 ,bibliography and index of ,texas geology3 ,univ4 ,texas ,pub4 #eiaj1 #bch pp4 99---- 7#aifd7 ,texas rocks and minerals3 ,univ4 ,texas1 ,bur4 ,econ4 ,geol4 ,guidebook ,no4 #f1 #aji pp4 ,gould1 ,c4 ,n4 7#aijb7 ,the geology and water resources of the eastern portion of the ,panhandle of ,texas3 ,u4 ,s4 ,geol4 ,survey ,water-,supply ,paper #aed1 #fd pp4 ---- 7#aijg7 ,the geology and water resources of the western portion of the ,panhandle of ,texas3 ,u4 ,s4 ,geol4 ,survey ,water-,supply ,paper #aia1 #gj pp4 99,matthews1 ,w4 ,h41 ,,iii 7#aifj7 ,texas fossils3 ,an amateur collector's handbook3 ,univ4 ,texas1 ,bur4 ,econ4 ,geol4 ,guidebook ,no4 #b1 #abc pp4 99,patton1 ,l4 ,t4 7#aibc7 ,the geology of ,potter ,county ,texas3 ,univ4 ,texas ,bull4 #bccj1 #ahj pp4 99,reed1 ,l4 ,c41 and ,longnecker1 ,o4 ,m4 7#aicb7 ,the geology of ,hemphill ,county1 ,texas3 ,univ4 ,texas ,pub4 #cbca1 #ih pp4 99,sellards1 ,e4 ,h41 ,adkins1 ,w4 ,s41 and ,plummer1 ,f4 ,b4 7#aicc7 ,the geology of ,texas1 ,vol4 ,i1 ,stratigraphy3 ,univ4 ,texas ,bull4 #cbcb 7,august #bb1 #aicb71 #ajjg pp4 ,west ,texas ,state ,university ,geological ,society 7#aifd7 ,palo ,duro ,field ,trip ,guidebook3 ,west ,texas ,state ,univ4 ,geol4 ,soc41 ,canyon1 #ah pp4 ---- 7#aifj7 ,geology of ,palo ,duro ,canyon ,state ,park and the ,panhandle of ,texas3 ,west ,texas ,state ,univ4 ,geol4 ,soc41 ,guidebook for #aiff ,,sasgs ,annual ,field ,trip1 ,april #ae-ag1 #aiff1 #eh pp4 ,smith1 ,a4 ,r4 7#aifg7 ,caves of ,palo ,duro ,canyon3 ,the ,texas ,caver1 ,abilene1 ,texas1 vol4 #ab1 pp4 #ade-adh4 ,,glossary ,abrasion--erosion of rock material by friction of solid particles moved by water1 ice1 wind1 or gravity4 ,absolute time--geologic time measured in years4 ,compare with relative time4 ,amphibians--cold-blooded four-footed animals which have gills in youth and lungs in maturity 7e4g41 frog74 ,anhydrite--the mineral calcium sulfate1 ,ca,s,o4 ,see ,gypsum4 ,anticline--an arch-like fold in the rocks1 with the beds dipping in opposite directions on the two sides4 ,aquifer--a water-bearing layer of porous and permeable rock4 ,aragonite--a form of calcium carbonate 7,ca,c,o74 ,archeozoic--the oldest known geological era2 early ,precambrian4 ,bedding plane--the plane of demarcation between two individual rock layers or strata4 ,calcite--a mineral composed of calcium carbonate1 ,ca,c,o4 ,caliche--an accumulation of calcium carbonate1 commonly white in color1 in the soil profile4 ,cenozoic--the latest era of geologic time1 containing the ,tertiary and ,quaternary ,periods and continuing to the present time4 ,chert--dense1 hard rock of very fine-grained silica1 usually in nodular form4 ,this material is also called flint4 ,concretion--a concentration1 usually spherical1 of mineral matter in sedimentary rocks1 produced by deposits from solution2 it is harder than the surrounding rock4 ,conglomerate--a sedimentary rock composed of rounded1 water-worn gravel1 usually mixed with sand1 and cemented together by another mineral substance4 ,coprolite--the fossilized excrement of animals4 ,eolian--pertaining to the erosion and the deposits resulting from wind action and to sedimentary rocks composed of wind-transported material4 ,epoch--a subdivision of a geologic period1 such as the ,pliocene ,epoch of the ,tertiary ,period4 ,era--a major division of geologic time4 ,all geologic time is divided into five eras3 the ,archeozoic1 ,proterozoic1 ,paleozoic1 ,mesozoic1 and ,cenozoic ,eras4 ,fluorescence--luminescence of a mineral during exposure to radiation 7such as from ultraviolet or ,x-rays74 ,fluvial deposit--sediment deposited by streams4 ,formation--a rock unit useful for mapping and distinguished primarily on the basis of lithologic character4 ,fossil--any remains or traces of plants or animals preserved in deposits of a past geologic age4 ,geode--a hollow stone1 usually lined or filled with mineral matter4 ,geologic age--the age of an object as stated in terms of geologic time 7e4g41 a ,pennsylvanian fern1 ,cretaceous dinosaur74 ,geologic time--all time which has elapsed since the first known rocks were formed and continuing until recent1 or modern1 times4 ,geologic time scale--record of the divisions of earth history4 ,gypsum--a mineral1 hydrated calcium sulfate 7,ca,s,o#b;,h,o74 ,see ,anhydrite4 ,hoodoo--a form produced by erosion of rock4 ,ice age--the ,pleistocene ,epoch of the ,quaternary ,period1 ,cenozoic ,era2 a time of extensive glaciation4 ,igneous rock--rocks which have solidified from lava or molten rock called magma4 ,joint--a fracture in a rock along which there has been no displacement on opposite sides of the break4 ,joint ,system--a series of two or more sets of joints passing through a rock mass and separating it into blocks of more or less regular pattern4 ,mass-wasting--erosion caused chiefly by gravity4 ,mesozoic--the geologic era between the ,paleozoic and ,cenozoic ,eras2 the 8,age of ,reptiles40 ,metamorphic rock--rock formed from igneous or sedimentary rocks that have been subjected to great changes in temperature1 pressure1 or chemical environment4 ,metamorphism--the process whereby rocks are changed physically by heat1 pressure1 or chemical environment into different kinds4 ,mineral--a naturally occurring inorganic substance possessing definite chemical and physical properties4 ,nodule--rounded lump of rock or mineral4 ,outcrop--the area where a particular rock formation comes to the surface4 ,paleontology--the science which deals with the study of fossils4 ,paleozoic--that era of geologic time following the ,proterozoic and preceding the ,mesozoic4 ,period--a basic unit of the geologic time scale into which the eras are divided1 such as the ,pennsylvanian ,period of the ,paleozoic ,era4 ,permian--the seventh and last period of the ,paleozoic ,era4 ,pleistocene--the first of the two epochs of the ,quaternary ,period1 and that which precedes modern time1 known as the ,great ,ice ,age4 ,pliocene--last and youngest epoch of the ,tertiary ,period of the ,cenozoic ,era4 ,proterozoic--youngest era of the ,precambrian2 follows the ,archeozoic ,era and precedes the ,cambrian ,period of the ,paleozoic ,era4 ,red beds--a general term for red sandstone1 shales1 etc41 which appear to characterize arid periods in the past4 ,ripple marks--wave-like corrugations produced in unconsolidated materials by wind or water4 ,rock--any natural aggregate of mineral matter1 usually consisting of a mixture of two or more minerals4 ,sandstone--sedimentary rock composed of cemented sand grains1 usually quartz4 ,sediment--material that has been deposited by settling from a transportation agent such as water or air4 ,sedimentary rock--rocks formed by the accumulation of sediments4 ,shale--a sedimentary rock formed by the hardening of mud and clay and usually tending to split into thin sheets or layers4 ,silica--an oxide of silicon 7,si,o74 ,siliceous--containing or pertaining to silica4 ,silt--fine muddy sediment consisting of particles intermediate in size between clay particles and sand grains4 ,siltstone--a very fine-grained sedimentary rock composed of silt grains1 and intermediate between shale and sandstone4 ,stratified rocks--sedimentary rocks2 those formed in beds1 layers1 or strata4 ,stratum--an individual layer of rock formation4 7,plural1 strata47 ,superposition1 law of--in an undisturbed sequence of rocks younger beds overlie older beds4 ,syncline--a trough-like fold in the rocks1 with the beds dipping inward on either side4 ,see ,anticline4 ,talus--a mass of rock debris commonly on slopes or at the base of a steep mountain or cliff4 ,topography--the configuration of a land surface4 ,unconformity--a break in the sequence of rock formations which separates younger strata from older ones2 caused primarily by removal of older rocks by erosion before those of a later sequence were laid down4 ,weathering--any natural process1 mechanical or chemical1 whereby rocks are disintegrated or decomposed into smaller particles and ultimately into clay and soil4 ,index ,a abrasion3 #cj ,adair1 ,john3 #f 8,age of ,mammals03 #bg alabaster3 #ag ancient man in ,palo ,duro ,canyon3 #c anhydrite3 #ah anticlines3 #ah ,apaches3 #a1 #c aquifer3 #bf ,arapahos3 #c ,archeozoic rocks3 #ac ,b 8blow sand03 #bh bottom load3 #bi ,brazos ,river3 #h ,buettneria3 #bb1 #bc1 #bd ,c calcite3 #bb caliche3 #bf camels3 #bg camping and picnicking3 #dc ,canyon1 ,texas3 #de ,capitol ,peak3 #a1 #ah1 #ai1 #ca1 #dj1 #db ,carboniferous ,period3 #af ,catarina ,cave3 #ai1 #cg1 #ch chemical weathering3 #cj chert3 #bf ,cheyennes3 #c ,civilian ,conservation ,corps3 #h ,colorado ,river3 #h comancheros3 #f1 #df ,comanches3 #a1 #c concretions3 #bb conglomerate3 #bd coprolites3 #bb ,coronado1 ,francisco ,vasquez de3 #c ,coronado ,lodge3 #a1 #ba1 #bf1 #cc1 #cd 8,cow ,cabins03 #da cross-bedding3 #ai1 #bj cross-stratification3 #ai ,d decomposition3 #cj ,devil's ,slide3 #ai1 #dj1 #dd ,devil's ,tombstone3 #dj differential erosion3 #ca1 #da disintegration3 #cj dugout1 ,col4 ,charles ,goodnight's3 #ci1 #dj ,e earth history3 #aj-ab ,eastern ,caprock ,escarpment3 #h erosion1 differential3 #ca1 #da ,f flash floods3 #bi fluorescence3 #bf fluvial sediments3 #bd ,fortress ,cliff3 #a1 #dj1 #db fossils3 #aj frost wedging3 #cj ,g geodes3 #bb geologic column3 #ab geologic time scale3 #aa1 #ab geomorphologist3 #bi ,goodnight1 ,colonel ,charles3 #a1 #ci1 #dj gypsum3 #ag ,h ,harper1 ,mrs4 ,ples3 #ce hematite3 #bb ,hester1 ,w4 ,a43 #a ,high ,plains3 #h hiking3 #dc history of park3 #c-h 8hoodoos03 #bc1 #ca ,horn1 ,ron3 #ce horseback riding3 #dc horses3 #bg hydration3 #ah1 #ca hydraulic action3 #cj ,i ,ice ,age3 #c igneous rocks3 #aj ,indian campground3 #ci ,indians of the ,plains3 #c ,j ,,ja ,ranch3 #f ,k ,kiowas3 #a1 #c ,l ,lighthouse1 ,the3 #bc1 #be1 #ci1 #da ,little ,sunday ,canyon3 #ci ,llano ,estacado3 #h ,m ,mackenzie1 ,colonel ,ranald3 #c mammals3 #bg ,marcy1 ,captain ,r4 ,b43 #f mass-wasting3 #ca mastodon1 shovel-jawed3 #bg mechanical weathering3 #cj metamorphic rocks3 #aj mortar hole3 #be ,o ,observation ,point3 #cc ,ogallala ,formation3 #ba1 #bc-bg1 #db opal3 #bf oxidation3 #ca ,p ,paleozoic ,era3 #ac ,palo ,duro ,canyon ,state ,park3 #g1 #ad1 #de ,panhandle-,plains ,historical ,museum3 #b1 #bg1 #de-df ,park ,entrance3 #cc park history3 #c-h ,park ,road #e3 #cc1 #ch1 #ej ,parker1 ,chief ,quanah3 #g ,pecos ,river3 #h pedestal rock3 #be petrified wood3 #bb photography3 #dc phytosaurs3 #bb picnicking and camping3 #dc ,pioneer ,amphitheatre3 #cc-cd ,plains ,indians3 #c ,pleistocene rocks3 #bh time3 #c ,pliocene ,epoch3 #bg ,prairie ,dog ,town ,fork of the ,red ,river3 #a1 #bi1 #ci ,precambrian rocks3 #ac principle of superposition3 #ac ,proterozoic rocks3 #ac psilomelane3 #bb ,q ,quartermaster ,formation3 #ab1 #ag-ai1 #bj1 #ba1 #ca1 #cf1 #cg1 #db1 #dd ,r ,red ,river3 #h1 #bi reduction halos3 #ai1 #bj ripple marks3 #ai ,rock ,garden1 ,the3 #bc1 #dj1 #dc ,rocky ,mountains3 #bd ,s saber-tooth cat3 #bg ,sad ,monkey1 ,texas3 #cf ,railroad3 #f1 #bj1 #bc1 #ce ,santana's ,face3 #bc1 #cg1 #ch satin spar3 #ag ,scenic ,drive1 ,the3 #cc sedimentary rocks3 #aj sediments3 #aj selenite3 #ag septaria3 #bb septarian concretions3 #bb shovel-jawed mastodon3 #bg ,sky ,ride1 ,the3 #cg ,sleeping ,indian3 #dj1 #db sloths3 #bg siliceous rocks3 #bg solution3 #bi ,spanish ,skirts3 #ai1 #cg suffosian3 #ai ,sunday ,canyon3 #dj superposition1 principle of3 #ac suspension3 #bi synclines3 #ah ,t talus3 #ca talus slopes3 #ca ,tecovas ,formation3 #ai-bb1 #cf1 #cg1 #db1 #dd ,texas ,panhandle3 #i ,texas ,panhandle ,heritage ,foundation1 ,inc43 #ce ,texas ,parks and ,wildlife ,department3 #b ,texas-,santa ,fe ,expedition3 #f ,timber ,mesa3 #a1 #bc1 #cg1 #ch time scale1 geologic3 #aa1 #ab tortoises3 #bg ,triassic ,peak3 #a1 #ce ,trujillo ,formation3 #bj1 #ba1 #bb-bc1 #cf1 #ch1 #db1 #dc ,turnaround1 ,the3 #a1 #da1 #dd ,u unconformities3 #ba ,w water crossings3 #ci weathering3 #cj ,west ,texas ,state ,university3 #de ,wolfin1 ,charles ,a43 #a ,footnotes #a,professor of ,geology1 ,lamar ,state ,college of ,technology1 ,beaumont1 ,texas4 #b;,entries marked with asterisk are published by the ,bureau of ,economic ,geology1 ,the ,university of ,texas at ,austin4 ,those not out of print are distributed at nominal sale price2 list sent on request4 ,illustration3 ,cover image1 ,aerial view of ,palo ,duro ,canyon ,transcriber's ,notes --,this book1 published without copyright notice1 is in the public domain4 --,silently corrected a few palpable typos4 --,added links to glossary entries4