,the ,geologic ,story of ,glacier ,national ,park ,cover ,,chief ,,mountain ,special ,bulletin ,no4 #c ,,glacier ,,natural ,,history ,,association ,price #be ,cents ,,the ,,geologic ,,story of ,,glacier ,,national ,,park ,by ,,james ,l4 ,,dyson ,head1 ,department of ,geology and ,geography ,lafayette ,college#a ,until recently a geologist was visualized by most people as a queer sort of fellow who went around the countryside breaking rocks with a little hammer4 ,fortunately1 the general public today has a much clearer picture of the geologist and his science1 but there are still many among us who mistakenly feel that geology is something too remote for practical application4 ,geology is the science of the ,earth4 ,it includes a history of our planet starting with its origin1 and a history of the life which has lived upon it4 ,from it we can determine the reason for every feature of the landscape and every rock structure underneath the surface1 and we can further learn what processes gave rise to them4 ,practically everything to be seen on the face of the ,earth owes its origin directly or indirectly to geological processes4 ,these may be grouped into two great categories3 ,internal forces or agents which raise1 lower1 bend1 and break the ,earth's crust2 and external1 more familiar agents such as water1 wind1 and ice1 which wear away the surface and carry the materials to another place--ultimately to the sea4 ,let us consider a few of the products of these geologic agents3 7#a7 ,the soil covering most of the landscape and furnishing the plant products which serve as our food2 7#b7 the solid rock1 so conspicuous in all mountain ranges2 7#c7 the hills1 the valleys1 and the mountains2 7#d7 all the streams1 ponds1 lakes--even the sea4 ,if you live in a place where man has covered up the rock and the soil evidence of geological processes is yielded by the buildings themselves1 whether they be of stone quarried from the ,earth's crust1 or of brick made from clay4 ,the stone and brick are supported by a framework of steel originally taken from a mine in the form of iron ore4 ,the concrete and asphalt of the roads came from rocks within the ,earth1 as did every drop of gasoline which plays so vital a part in world affairs today4 ,even those commonplaces of ,american life1 the bottle and the tin can1 are products of geology4 ,as you read this you need look only at your watch or perhaps an item of jewelry which you wear to see something--gold1 silver1 platinum1 a diamond or other gem stone--which is a part of geology4 ,thus1 from here it is a short step to the realization that a number of geologic processes and agents working over long periods of time have given rise to innumerable features and structures ranging from the loftiest mountains down to the smallest hills and valleys2 from the soil which grows our food to the gasoline and coal which feed our industries2 from our huge iron ore deposits down to the much smaller1 but now no less significant1 deposits of uranium4 ,how is all this related to a national park8 ,nowhere within our land can the accomplishments of the great geological processes1 or their present-day operation1 be seen to better advantage than in many of our national parks and monuments4 ,in fact1 it is for this reason principally that many of them were established4 ,notable is ,grand ,canyon ,national ,park1 containing the most spectacular part of the ,colorado's mile-deep canyon cut during the past million or so years through a series of rocks which themselves record a billion or more years of ,earth history4 ,mount ,rainier is the largest volcano in the ,united ,states4 ,on it glaciers are now wearing away materials formerly extruded and piled up to spectacular height by volcanic forces4 ,crater ,lake lies in the sunken throat of a volcano which at one time probably rivaled ,rainier in size4 ,in ,carlsbad ,caverns and ,mammoth ,cave ,national ,parks are two of the world's largest caverns which clearly demonstrate the tremendous effectiveness of subsurface water in dissolving limestone4 ,bryce ,canyon and ,zion ,national ,parks and the ,badlands ,national ,monument illustrated on a much smaller but no less spectacular scale than the ,grand ,canyon the wonderful erosive power of running water4 ,in ,grand ,teton one can see a huge block of the crust which has been raised thousands of feet along a high-angle fault1 and at ,lassen ,peak in ,california and ,craters of the ,moon in ,idaho there are exhibited some of the most recent volcanic features north of the ,rio ,grande4 ,despite ,yellowstone's wildlife and fishing it is best known perhaps for its geysers4 ,this brief list is by no means complete1 for something of prime geologic interest can be found in almost every national park and monument4 ,now we come to ,glacier ,national ,park4 ,within its boundaries there perhaps is exhibited a greater variety of geologic features than in any of the others4 ,much of the park lies above timberline so that the rocks which comprise its mountains are exposed to view4 ,held within these superb mountains is an entertaining geologic story which they are anxious and willing to tell us4 ,all we need to do is unlock the door with the key the geologist gives us and then go see for ourselves4 ,why do the mountains rise so precipitously above the plains8 ,what is that conspicuous black band across the faces of so many of the peaks1 and how did it get there8 ,why are some of the rocks so red8 ,the answers to these and other questions come out as the geologic story unfolds4 ,the ,american people are interested in this story for they realize that to understand what they see is to increase their enjoyment thousandfold4 ,chart of ,geologic ,time 7,,for ,a ,,chronological ,,order ,,of ,,events1 ,,the ,,chart ,,should ,,be ,,read ,,from ,,bottom ,,to ,,top7 ,,eras ,,periods ,,dates ,,events ,,in ,,glacier ,,park ,,area ,,cenozoic ,the ,present ,post ,glacial ,erosion of the mountains2 formation of alluvial fans and talus cones4 #ae1jjj ,b4,c4 ,pleistocene ,birth of modern glaciers4 ,appearance of present forests4 #a1jjj1jjj ,b4,c4 ,pliocene ,extensive glaciation4 ,formation of lakes1 waterfalls1 horn peaks1 cirques4 ,valleys scoured deeply by glaciers4 ,miocene ,disappearance of forests4 ,oligocene ,mountains worn down1 raised1 eroded again4 ,eocene ,lewis overthrust probably occurred early in ,eocene4 #eh1jjj1jjj ,b4,c4 ,,mesozoic ,great mountain building 7,rocky ,mountain revolution7 by forces which eventually formed ,lewis overthrust4 ,sea withdrew and never again returned4 ,thick accumulation of marine sediments4 ,invertebrates abundant in sea4 ,expansion of the sea4 ,cretaceous #abg1jjj1jjj ,b4,c4 ,jurassic ,triassic ,dinosaurs probably inhabited park and nearby area4 #ahb1jjj1jjj ,b4,c4 ,,paleozoic ,seas covered region during much of era4 ,permian ,carboniferous #bee1jjj1jjj ,b4,c4 ,devonian ,silurian ,ordovician ,cambrian #eaj1jjj1jjj ,b4,c4 ,,proterozoic ,sea withdrew and region was eroded at end of era4 ,area covered by sea in which ,belt sediments were deposited4 ,algae lived in sea4 ,intrusions 7diorite sill and dikes7 from flows 7,purcell7 of igneous material4 ,,archeozoic #b1aaj1jjj1jjj ,b4,c4 8 ,,eras1 ,,periods1 ,,and ,,dates ,,in ,,this ,,chart ,,are ,,in ,,accordance ,,with ,,those ,,which ,,have ,,been ,,adopted ,,as ,,official ,,by ,,the ,,national ,,park ,,service4 ,the ,story ,begins ,the most striking feature of the mountains--certainly the one which comes first to a visitor's attention--is the color banding4 ,no matter where one looks this feature greets his view4 ,if he enters the park at the ,st4 ,mary ,entrance1 there ahead on the sides of ,singleshot and ,east ,flattop ,mountains are white and purple bands4 ,should he enter first the ,swiftcurrent ,valley1 he would soon note the banding in the mountains lying to his right and left1 and finally culminating in the precipitous ,garden ,wall at the head of the valley4 ,the visitor soon realizes that every mountain within the park is composed of rock layers of various colors4 ,with very few exceptions these strata are of sedimentary origin2 that is1 they accumulated by depositions of muds and sands in a body of water and are now mainly limestones1 shales1 and sandstones4 ,these sedimentary rocks all belong to a single large unit known as the ,belt series1 so named because of exposures in the ,little ,belt and ,big ,belt ,mountains farther south in ,montana4 ,in ,glacier ,national ,park these rocks1 which have a maximum thickness of more than #bj1jjj feet1 are in the form of a large syncline 7downfold71 the east and west edges of which form the crests of the ,lewis and ,livingstone ,ranges 7,figure #c;,d74 ,throughout the large area of western ,montana1 northern ,idaho1 and southern ,british ,columbia where ,belt rocks occur1 they are important mountain-makers4 ,in addition to the ranges already mentioned they are the principal rocks in many others1 including the ,mission1 ,swan1 and ,flathead in the region south of ,glacier ,park2 the ,bitterroot and ,coeur d',alene between ,idaho and ,montana2 and the ,purcell in ,british ,columbia4 ,further1 rocks of similar age form the core of the ,uinta ,range in ,utah and the lower section of the ,grand ,canyon in ,arizona4 ,during the ,proterozoic ,era of ,earth history a long1 narrow section of ,north ,america extending from the ,arctic ,ocean southward1 probably as far as ,arizona and southern ,california1 slowly sank to form a large1 shallow1 sea-filled trough known as a geosyncline 7,figure #a74 ,streams from adjacent lands carried muds and sands into the sea1 at times almost completely filling it4 ,inasmuch as thousands of feet of sediments were deposited1 the geosyncline must have continued to sink throughout the period of sedimentation4 ,eventually the muds were compacted into shales1 or limestones if they contained a lot of lime1 and the sands into sandstones4 ,these are the rocks we now know as the ,belt series4 ,the surfaces of many of the sandstone layers are covered with ripple marks which could have been made only by wave and current action in shallow water4 ,mudcracks on many of the shale beds prove that at times the sediments1 probably near the mouths of rivers were exposed to the air long enough to dry out4 ,great thicknesses of limestone and numerous fossils of calcareous algae1 primitive marine plants1 are evidences that the body of water was a sea4 ,,figure #a4 ,,belt ,,geosyncline ,throughout the geologic past the appearance and disappearance of seas on the continents have been frequent events4 ,in fact such changes are slowly taking place even today4 ,hudson ,bay and the ,baltic and ,north ,seas are examples of shallow seas situated on the continents4 ,the area around ,hudson ,bay is rising2 as attested by the fact that some of the fish weirs constructed in water along the shore during the past several hundred years are now a considerable distance inland4 ,we know also that our ,atlantic coast has been subsiding for a number of years at an annual rate of about #j4jb feet4 ,to be sure1 these movements are slow1 but if continued over a long period they might conceivably make some rather profound changes1 even as the birth and death of the ,belt sea4 ,within ,glacier ,national ,park the ,belt series is divided on the basis of lithologic differences into six distinct formations4 ,because each has a characteristic color1 these formations can easily be identified1 often from distances of several miles4 ,usually two1 sometimes three or four1 of them comprise a single mountain1 the oldest always at the mountain base and the youngest on the summit1 this being the relative position in which they were deposited in the form of sediment4 ,illustration3 ,,mud ,,cracks ,,on ,a ,,layer ,,of ,,the ,,appekunny ,,formation 7,,photo ,,by ,c4 ,l4 ,,fenton4 ,,our ,,amazing ,,earth4 ,,doubleday ,,and ,,co47 ,illustration3 ,,ripple ,,marks ,,on ,a ,,layer ,,of ,,the ,,shepard ,,formation ,,near ,,logan ,,pass4 ,,their ,,assymmetrical ,,form ,,indicates ,,formation ,,by ,,currents ,,in ,,shallow ,,water4 7,,dyson ,,photo7 ,the ,belt ,formations ,,altyn ,,formation4 ,this is the oldest of the several formations and thus occupies a stratigraphic position at the base of the entire series4 ,it is composed mainly of sandy dolomites 7magnesian limestones7 and limestones which weather to a light buff color4 ,it outcrops all along the base of the eastern front of the ,lewis ,range and comprises the entire block of ,chief ,mountain4 ,because of its comparatively great resistance to weathering and erosion it usually forms a conspicuous ridge or terrace wherever it crosses a valley4 ,in the ,swiftcurrent ,valley it forms the dam which holds in ,swiftcurrent ,lake and creates ,swiftcurrent ,falls4 ,in ,two ,medicine ,valley the highway crosses a similar terrace which gives rise also to ,trick ,falls4 ,in the ,st4 ,mary ,valley it creates the ,narrows and forms the imposing wall in lee of which ,east ,glacier ,campground is located4 ,the rock of this formation can best be examined on the ridge immediately east of ,many ,glacier ,hotel 7between hotel and parking lot7 and above ,swiftcurrent ,falls4 ,its average thickness is about #b1cjj feet4 ,,appekunny ,,formation4 ,lying on top of the ,altyn are #c1jjj or more feet of prevailing greenish shales and argillites#b comprising the ,appekunny formation4 ,slabs of these rocks1 because of their great hardness1 have been used as flagstones in the walks at the ,many ,glacier ,ranger ,station and adjacent ,park ,service residential area4 ,mud cracks and ripple marks are common4 ,the formation is prominent on the side of ,singleshot ,mountain near the ,st4 ,mary entrance to the park1 and everywhere immediately overlying the lighter-hued ,altyn along the east edge of the ,lewis ,range where1 especially when seen from a distance1 it appears to have a purplish color4 ,it also outcrops along the western base of the ,livingstone ,range 7,figure #c;,d71 but such exposures are as a rule obscured by a cover of dense forest4 ,accessible outcrops can readily be examined along ,going-to-the-,sun ,highway for several miles east of ,sun ,point and near ,mc,donald ,falls1 and also along the lower part of the ,grinnell ,glacier trail4 ,,grinnell ,,formation4 ,because of their dominantly red color1 the shaly argillites which comprise the bulk of this formation are the most conspicuous rocks in the park4 ,they lie immediately on top of the ,appekunny and although their thickness varies considerably it is greater than #c1jjj feet in several localities4 ,interbedded with the red argillites are thin white layers of quartzite1 a former sandstone which has been converted by pressure into an extraordinarily hard1 dense rock4 ,mud cracks1 ripple and current marks1 raindrop impressions1 and other features made while the sediments were accumulating are common4 ,the red color is due to abundant iron oxide occurring mainly as a cement between the sand and mud grains4 ,all the rocks of ,glacier ,park contain some iron1 or rather contain iron-bearing minerals4 ,these minerals have various colors unless they have been oxidized1 in which case the color is red or brown4 ,oxidation of the ,grinnell formation probably took place while the mud was accumulating and during those periods when it was exposed to the atmosphere4 ,at such times also the mud dried and cracked1 the marks of which are so prominent on the surfaces of the layers today4 ,the ,grinnell formation seems to be everywhere4 ,in the ,many ,glacier region it comprises the bulk of ,grinnell ,point1 ,altyn ,peak1 and ,mount ,allen1 and is no less striking in the bases of ,mount ,wilbur and the ,garden ,wall4 ,ptarmigan ,tunnel is drilled through it1 and the trails to ,grinnell ,glacier1 ,cracker and ,iceberg ,lakes cross it4 ,redrock ,falls1 on the trail to ,swiftcurrent ,pass1 and ,ptarmigan ,falls on the ,iceberg ,lake trail drop over several of its highly colored layers4 ,from the ,blackfeet ,highway on top of ,two ,medicine ,ridge one can see the dark red rocks of this formation capping the summits of ,rising ,wolf and ,red ,mountains4 ,even from the valley floor it is just as noticeable4 ,sinopah ,mountain standing alone and impressive across the lake from ,two ,medicine ,chalets carries the red banner of the ,grinnell formation4 ,these red rocks constitute an important scenic feature for many miles along ,going-to-the-,sun ,highway4 ,if one begins his trip on this highway at its east entrance he soon finds himself in the midst of a group of imposing red peaks--,goat and ,going-to-the-,sun on the right1 ,red ,eagle and ,mahtotopa on the left4 ,the road crosses the formation along a mile and a half stretch just west of ,baring ,creek bridge4 ,innumerable loose slabs of red rock along the side of the road contain excellent mud cracks and ripple marks4 ,near ,avalanche creek on the west side of ,logan ,pass the highway crosses the ,grinnell where it comes to the surface on the western limb of the big syncline4 ,the formation is well exposed in the vicinity of ,sperry ,chalet and ,glacier4 ,it forms all the mountains surrounding the basin in which the chalet is located1 and the trail from chalet to glacier lies wholly on it4 ,at the glacier intensely folded white quartzite layers and red argillites are very conspicuous4 ,the visitor can readily trace the ,grinnell from place to place throughout the entire park area1 and can thus easily visualize that it as well as all other formations at one time filled the intervening spaces between the mountains4 7,see color of cover pages47 ,,siyeh ,,formation4 ,next above the ,grinnell is a thick limestone formation which1 because of its weathered buff color1 stands out in sharp contrast to the red beds upon which it rests4 ,it is the greatest cliff-maker in the park and in several places its entire thickness of #d1jjj feet may be exposed in a single nearly vertical cliff4 ,since it is younger than the three preceding formations1 it is confined mainly to the higher elevations1 capping many of the loftiest peaks within the ,lewis and ,livingstone ,ranges4 ,in the ,many ,glacier area such peaks are ,mount ,gould and the ,garden ,wall1 ,mounts ,siyeh1 ,grinnell1 ,allen1 ,wilbur1 and ,henkel4 ,a number of others1 including ,little ,chief1 ,jackson1 ,gunsight1 ,fusillade1 ,going-to-the-,sun1 ,piegan1 ,pollock1 ,cannon1 and ,heavens ,peak1 are visible from ,going-to-the-,sun ,highway4 ,the huge peaks--,kinnerly1 ,kintla1 ,carter1 and ,rainbow--which stand guard at the heads of ,kintla and ,bowman ,lakes are composed of the ,siyeh4 ,the list also includes ,cleveland1 highest and largest of all4 ,illustration3 ,,algae ,,colonies ,,in ,,siyeh ,,limestone ,,near ,,grinnell ,,glacier4 7,,dyson ,,photo7 ,illustration3 ,,gently ,,tilted ,,strata ,,of ,,the ,,siyeh ,,formation ,,in ,,grinnell ,,mountain4 7,,dyson ,,photo7 ,within the ,siyeh there is a bed1 averaging about #fj feet thick1 composed almost entirely of fossil algae which apparently formed an extensive reef or biostrome on the floor of the shallow ,belt ,sea4 ,the algae colonies are in the form of rounded masses up to several feet in diameter and bear a crude resemblance externally and internally to a head of lettuce or cabbage4 ,geologists know these algae by the genus name ,collenia4 ,because of the rounded and smoothed surfaces on these colonies1 mountain climbers frequently find the reef difficult to cross4 ,it appears as a distinct light gray horizontal band on the east face of ,mount ,wilbur about midway between the base of the cliff and the peak's summit1 where it can easily be seen from ,many ,glacier ,hotel and ,swiftcurrent ,camp4 ,it is also discernible on the ,pinnacle ,wall above ,iceberg ,lake and in ,mount ,grinnell4 ,the ,swiftcurrent ,pass trail crosses it just east of the pass1 and it is also exposed along ,going-to-the-,sun ,highway below the big switchback on the west side of ,logan ,pass where attention is directed to it by a sign4 ,unweathered portions of the reef rock are light blue4 ,a similar but thinner reef outcrops at ,logan ,pass near the start of the ,hidden ,lake trail4 ,although most of the fossil algae occur in the ,siyeh they are present in the younger formations and also in the ,altyn4 ,other than algae the only undoubted fossils of the ,belt series within ,glacier ,national ,park are burrows probably made by worms4 ,they are rare and are restricted mainly to the ,siyeh formation4 ,illustration3 ,,fossil ,,algae ,,in ,,siyeh ,,formation1 ,,hole-,,in-,,the-,,wall ,,basin4 7,,the ,,rock ,,book ,,by ,c4 ,l4 ,,fenton ,,and ,m4 ,a4 ,,fenton1 ,,doubleday ,,and ,,co47 ,at the top of the ,siyeh are several hundred feet of sandy and shaly beds1 mostly reddish in color1 grouped by some geologists into a distinct formation known as the ,spokane4 ,at ,logan ,pass it is about #gjj feet thick and is well exposed in the lower parts of ,clements and ,reynolds ,mountains1 and at the site of the former ,clements ,glacier4 ,,shepard ,,formation4 ,several hundred feet of limy beds which weather yellow-brown lie on top of the ,siyeh4 ,although named for outcrops on the cliff above ,shepard ,glacier 7south of ,stoney ,indian ,pass and near the site of the old ,fifty-,mountain tent camp7 the formation is exposed on the summit of ,swiftcurrent ,mountain at the head of ,swiftcurrent ,valley1 on ,reynolds and ,clements ,mountains near ,logan ,pass1 and on ,citadel and ,almost-a-,dog1 visible from ,going-to-the-,sun ,highway in ,st4 ,mary ,valley4 ,the formation is replete with mud cracks and ripple marks4 ,some rock surfaces exhibit two and three sets of the latter4 ,,kintla ,,formation4 ,these beds have the same bright red color as those of the ,grinnell4 ,however1 because they are the youngest rocks of the ,belt series they outcrop only on a few mountaintops1 and inasmuch as these are mainly in the northwest part of the park1 comparatively few people have noticed this formation4 ,visitors to ,cameron ,lake in ,waterton ,lakes ,national ,park can see it in the red north wall of ,mount ,custer4 ,the mountains around colorful ,boulder ,pass and ,hole-in-the-,wall ,basin are likewise composed of it4 ,within the rocks of this formation there is a great abundance of small cubes believed to be casts of salt crystals which formed when the sediments were accumulating4 ,their presence indicates an arid climate and intensive evaporation of the sea1 similar to the condition at ,great ,salt ,lake today4 ,igneous ,rocks of the ,belt ,series ,not all of ,glacier ,park's rocks accumulated slowly and quietly as sediment in a body of water4 ,at many places1 interbedded with and cutting across the sediments1 there are bodies of igneous rock which reached their present position in the form of hot molten material forced up from deep within the crust4 ,illustration3 ,,columnar ,,section ,,of ,,belt ,,rocks ,,proterozoic ,,kintla #hfj' ,red argillite ,,shepard #fjj' ,buff limestone ,,purcell #bej' ,black lava ,,siyeh #djjj' ,dark diorite bordered by white altered limestone ,blue limestone4 ,weathers buff ,,grinnell #afjj-cjjj' ,red argillite and white quartzite ,,appekunny #bejj' ,green argillite4 ,some white quartzite ,,altyn #bcjj' ,gray limestone4 ,weathers buff ,,purcell ,,lava4 ,soon after the youngest layers of ,siyeh limestone had accumulated on the floor of the sea and while they were still under water1 a mass of molten rock was squeezed up from far below and extruded in the form of a submarine lava flow over the recently accumulated sediments4 ,several times this lava poured out forming a total thickness varying between #ej and #bge feet4 ,one of the best exposures is on the west side of ,swiftcurrent ,pass and in ,granite ,park just west and northwest of the chalet4 ,in fact it is this lava flow which gives the name1 albeit wrongly1 to ,granite ,park4 ,the material of the flow is very fine-grained and dark 7basic71 in contrast to the light color and coarse grain of granite4 ,nonetheless1 many prospectors are wont to call every igneous rock1 regardless of its composition1 a granite4 ,a number of ellipsoidal structures 7pillows7 up to two feet in diameter within this lava indicate that it was extruded under water4 ,the ,purcell is thickest in the vicinity of ,boulder ,pass1 where the trail traverses its ropy and stringy surface for a distance of several hundred yards4 ,later1 after the ,shepard and part of the ,kintla formation were laid down on top of the ,purcell1 another similar flow spread over the sea floor4 ,,diorite ,,sill4 ,few persons visit the park without noticing the pronounced black layer1 within the ,siyeh formation1 present on many of the high peaks4 ,it is most in evidence on the face of the ,garden ,wall viewed from the vicinity of ,many ,glacier ,hotel1 although it is plainly visible also in ,mount ,wilbur and the wall above ,iceberg ,lake4 ,passengers on the ,waterton ,lake launch can see it cutting across the stupendous north face of ,mount ,cleveland4 ,from ,going-to-the-,sun ,highway it can be seen on ,mahtotopa1 ,little ,chief1 ,citadel1 ,piegan1 and ,going-to-the-,sun ,mountains1 and on the west side of the ,garden ,wall1 where it also forms the cap of ,haystack ,butte4 ,it is everywhere about #ajj feet thick1 and thus can be used as a very accurate scale for determining the height of mountains on which it is discernible4 ,this imposing layer of rock1 unlike the lava1 never reached the surface in a molten state1 but was intruded between beds of sedimentary rock and thus became a sill instead of a flow4 ,we need only a glance to determine its intrusive nature4 ,wherever it occurs it is bordered at top and bottom by thinner gray layers4 ,these are ,siyeh limestone which was changed to marble by the tremendous heat of the diorite during its intrusion4 ,this effect is termed contact metamorphism by geologists4 ,because this contact-metamorphosed zone is at both top and bottom of the sill we know the latter was intruded into the adjacent rocks4 ,lava flows1 even though covered later by sediments1 of course alter only the underlying rocks4 ,illustration3 ,,the ,,garden ,,wall ,,and ,,grinnell ,,glacier4 ,,the ,,wall ,,is ,,composed ,,of ,,siyeh ,,limestone ,,above ,,the ,,level ,,of ,,the ,,glacier ,,and ,,the ,,grinnell ,,formation ,,below ,,it4 7,,dyson ,,photo7 ,the sill can readily be examined in a number of places where trails cross it1 notably at ,swiftcurrent and ,piegan ,passes1 and north of ,granite ,park near ,ahern ,pass4 ,but nowhere is it as accessible as on ,logan ,pass4 ,it lies beneath the parking lot at a depth of only a few feet1 and is exposed on both sides of the pass4 ,to inspect it1 one need walk only about #bjj yards along the trail leading to ,granite ,park4 ,in a distance of less than #ajj feet the trail traverses from fresh ,siyeh limestone across the entire altered 7contact-metamorphosed7 zone1 here #ab to #bj feet wide1 into the center of the sill4 ,all parts of the sill and adjacent rocks can readily be examined and studied in detail at this site4 ,illustration3 ,,top ,,of ,,the ,,diorite ,,sill ,,of ,,blackfoot ,,glacier4 ,,the ,,man ,,is ,,standing ,,on ,,the ,,sill4 ,,light ,,rock ,,overlying ,,sill ,,is ,,contact-,,metamorphosed ,,siyeh ,,limestone4 7,,dyson ,,photo7 ,a number of dikes#c of ,belt age1 some of which undoubtedly were feeders to the sill and flows1 cut vertically up through the sedimentary formations4 ,some of the dikes are less resistant to weathering and erosion than the rocks surrounding them2 consequently their more rapid removal results in the formation of narrow vertical chimneys or recesses which appear as snow-filled chutes on the mountainsides in spring and early summer4 ,such a feature almost invariably indicates the presence of a dike4 ,from ,many ,glacier ,hotel one of these can be seen on the red mountain in front of ,mount ,wilbur4 ,another1 #a1ejj feet high1 transects the ,pinnacle ,wall at the outlet of ,iceberg ,lake4 ,the dike which forms this impressive chute is less than thirty feet wide4 ,though not so conspicuous as the sills some of these dikes are of interest because they contain various ore minerals1 principally copper1 which today form small deposits along their borders4 ,about the beginning of the century these were responsible for a short-lived mining boom1 the best known vestige of which is the remains of the mill at ,cracker ,lake4 ,the old ,cracker ,mine1 with entrance now caved in1 was driven along a dike which has a width of over #ajj feet4 ,from the boat landing at the head of ,josephine ,lake the dump of another mine appears as a tiny gray-green mound on a narrow shelf high on the precipitous wall of ,grinnell ,point4 ,like the ,cracker ,mine this one was dug along the edge of a similar but smaller dike4 ,all these deposits are insignificant in size and of no commercial value4 ,had they been important this great area might never have been set aside as a national park4 ,illustration3 ,,mount ,,wilbur ,,and ,,the ,,pinnacle ,,wall ,,viewed ,,from ,,many ,,glacier ,,hotel4 ,,the ,,upper ,,part ,,of ,,appekunny ,,and ,,all ,,of ,,the ,,grinnell ,,and ,,siyeh ,,formations ,,are ,,visible4 ,,the ,,snow-,,filled ,,chute ,,left ,,of ,,the ,,word ,,grinnell ,,is ,,formed ,,by ,,the ,,same ,,dike ,,which ,,passes ,,through ,,the ,,pinnacle ,,wall4 7,,hileman ,,photo1 ,,courtesy ,,glacier ,,park ,,co47 ,the ,story ,continues ,for the succeeding several hundred million years the geologic history of ,glacier ,national ,park is rather obscure1 but additional ,belt sediments apparently were deposited before uplift of the area caused the sea to withdraw4 ,following this event many feet of the younger ,belt sediments were removed by erosion4 ,the sea probably returned and received more sediments during much of the ,paleozoic ,era1 although no trace of these rocks has been found inside the park boundaries4 ,,cretaceous ,,rocks4 ,not until the ,cretaceous period of ,earth history1 about #ajj million years ago1 did the geologic record again become clear4 ,at that time a great thickness of mud and sand was deposited in the geosyncline burying deeply the ancient ,belt and other rocks which had accumulated as sediment during the preceding several hundred million years4 ,life had made tremendous advances in this interval1 and the abundance of fossils in ,cretaceous rocks indicates that the sea swarmed with shelled creatures during that period4 ,,the ,,lewis ,,overthrust4 ,toward the end of ,cretaceous time tremendous crustal forces1 principally from the west1 were directed against the geosyncline with the result that its rocks were compressed and uplifted1 converting the site of the former sea into a mountainous region4 ,similar activity took place throughout the length and breadth of the entire geosyncline1 which resulted in the formation of the ,rocky ,mountain system stretching between ,mexico and ,alaska4 ,a number of mountains were formed on other continents during this period4 ,so widespread and tremendous was the deformation1 especially in the present day ,rocky ,mountain region1 that it is known as the ,rocky ,mountain1 or ,laramide 7after the ,laramie ,range in ,wyoming71 revolution4 ,mountain-building forces continued for several million years in the ,glacier ,park area1 finally squeezing the rocks into a great fold 7anticline74 ,continued pressure from the west overturned the fold and put additional strain on the rock layers1 eventually causing them to break along a great low-angle fault4 ,the western limb of the fold1 now a great slice of the crust1 was driven upward and eastward over the eastern limb ultimately reversing the order of rock layers by placing older on top of younger ones 7,figure #c74 ,these younger layers are ,cretaceous shales and sandstones underlying the plains immediately east of the mountains4 ,the mountains themselves have been carved by streams and glaciers from the ,belt formations comprising the upper block of older rock1 that slice of the crust which has been moved more than #ae miles toward the east4 ,the surface over which it was pushed is the ,lewis overthrust4 ,at the time this great break occurred the part of it now exposed in ,glacier ,national ,park was deeply buried4 ,it was long after that when removal by erosion of overlying ,belt rocks1 possibly several thousand feet of them1 finally exposed the fault4 ,,figure #b4 ,,map ,,of ,,waterton-,,glacier ,,international ,,peace ,,park ,,legend #a4 ,,trace ,,of ,,lewis ,,overthrust #b4 ,,alluvial ,,fans #c4 ,,range ,,crests #d4 ,,highways ,movement along this fault was slow--so slow that had people been present at the time they probably would not have been aware that anything of an unusual nature was occurring4 ,occasionally along many large faults1 however1 there is sudden movement of small magnitude1 usually not more than a few inches1 but strong enough to vibrate the crust4 ,these vibrations are earthquakes1 and their frequent occurrence in ,california and elsewhere along the ,pacific coast indicates the presence of numerous active faults4 ,their occurrence also in the northern ,rockies1 as at ,helena1 ,montana in #aice and #aicf1 attests to the fact that some of the faults here are still active4 ,the ,lewis overthrust comes to the surface at the base of the ,altyn formation along the entire precipitous east front of the ,lewis ,range and can be traced nearly #ajj miles northward into ,canada and for almost an equal distance south of the park4 ,the section lying within the park is tilted very gently toward the southwest1 the angle of dip seldom exceeding ten degrees4 ,in some places it is practically horizontal4 ,for this reason the lower courses of all the largest1 and some of the small1 valleys on the east side of the ,lewis ,range have been cut entirely through the upper block 7overthrust7 of ,belt rocks down into the weak ,cretaceous shales underneath4 ,this causes the trace of the overthrust to be very sinuous and also accounts for the deep indentations in the mountain front formed by ,swiftcurrent1 ,st4 ,mary1 ,two ,medicine1 and other valleys4 ,the floors in the lower courses of these valleys1 because they lie below the level of the thrust surface1 are composed of ,cretaceous shales4 ,in most places these rocks are covered by glacial moraine1 but they are exposed along the highway from ,babb into the ,swiftcurrent ,valley1 especially along the shore of ,sherburne ,reservoir and near the entrance station4 ,because these shales readily disintegrate when exposed to the atmosphere they give rise to slumps and landslides which1 although of small proportions1 cause a great deal of damage to the highway1 sections of which must be rebuilt annually4 ,at most damaged spots along the route the shales appear as a dark mud or clay in the roadcuts4 ,the bumpy topography of the whole slope lying north of the road has been formed by innumerable such small landslides4 ,a deep well located near ,cameron ,falls in ,waterton ,townsite 7,waterton ,lakes ,national ,park7 about one mile west of the edge of the mountains passes through #a1ejj feet of ,belt rocks and then penetrates the ,lewis overthrust and the ,cretaceous shales beneath4 ,in the southern part of ,glacier ,national ,park just north of ,marias ,pass1 ,debris ,creek has cut a hole or window 7known as a fenster by geologists7 through the overthrust block 7,figure #b74 ,thus a small area of ,cretaceous rock completely surrounded by the ,belt series lies within the mountains4 ,this is the only such ,cretaceous outcrop in the park1 but like the well at ,waterton1 it serves as a reminder that the rocks of this period are everywhere present under the mountains1 and their surface constitutes the sliding board over which the upper1 more massive block of ,belt rocks was pushed4 ,and so we see that the mountains of ,glacier ,national ,park1 unlike many of the world's great ranges1 have no roots1 for they rest on a base of greatly different and much less resistant material1 the ,cretaceous shales4 ,presumably the ,lewis overthrust and ,cretaceous rocks beneath it would be penetrated by a well drilled anywhere within the mountains1 although in the ,livingstone ,range the depth of such a well would be very great 7,figure #c;,d74 ,,figure #c4 ,,history ,,of ,,lewis ,,overthrust ,a ,,hypothetical ,,section ,,near ,,the ,,close ,,of ,,cretaceous ,,time4 ,b ,,pressure ,,from ,,west ,,creates ,,large ,,fold ,,and ,,overturns ,,it ,,towards ,,east4 ,,the ,,new ,,mountains ,,are ,,cut ,,down ,,by ,,erosion4 ,c ,,continued ,,pressure ,,breaks ,,the ,,strata ,,and ,,the ,,lewis ,,overthrust ,,is ,,formed4 ,,dotted ,,line ,,shows ,,approximate ,,present ,,outline ,,of ,,surface ,d ,,section ,,across ,,the ,,park ,,showing ,,relationships ,,of ,,rock ,,formations ,,and ,,the ,,lewis ,,overthrust 7,,vertical ,,scale ,,greatly ,,exaggerated7 ,erosion in the eastern part of the overthrust block1 in addition to producing its crenulated edge1 has left several isolated remnants 7outliers7 east of the main mass of the mountains4 ,the best known of these is ,chief ,mountain situated near the northeast corner of the park several miles west of the ,chief ,mountain ,international ,highway4 ,it is a mass of ,altyn limestone rising vertically on its east1 south and north sides for a distance of #a1ejj feet4 ,the ,lewis overthrust is well exposed all around its base4 ,two smaller pinnacles immediately to the west are similar outliers1 and1 like ,chief ,mountain1 were once part of the main mass of the ,lewis ,range 7,figure #c;,d and cover sketch74 ,divide ,peak1 at the west end of ,hudson ,bay ,divide1 is another outlier4 ,it1 too1 is composed entirely of the ,altyn formation4 ,although the ,lewis overthrust is exposed in a great number of places very few of these are easily accessible1 and at only one does a trail provide a close approach to the actual contact between ,belt and ,cretaceous rocks4 ,the latter site lies along ,roes ,creek only a few hundred yards from ,east ,glacier ,campground4 ,before reaching the fault at the base of a high cliff of ,altyn limestone1 the trail crosses several outcrops of ,cretaceous sandstone replete with fossil pelecypods 7clams7 and gastropods 7snails74 ,the fault surface is covered by loose rock where the trail crosses it1 but on the opposite side of the stream a zone of crushed ,altyn limestone and ,cretaceous shale is visible4 ,from ,u4 ,s4 ,highway ,no4 #b just east of ,marias ,pass an excellent distant view of the thrust may be obtained4 ,about three miles to the north it appears as a nearly horizontal line high on the side of ,summit ,mountain4 ,above it is a vertical cliff in which white ,altyn and red ,grinnell are prominent1 and below is a gentler slope composed of gray-brown ,cretaceous shale4 ,cretaceous rocks with relatively low resistance to ,earth stresses1 were strongly crumpled and folded during the period of overthrusting4 ,the folded zone extends several miles eastward from the mountains 7,figure #c ,d71 and may be seen to good advantage along ,blackfeet ,highway on the north side of ,two ,medicine ,ridge1 where a series of thin shales and sandstones has been squeezed into anticlines and synclines4 ,it is because of the ,lewis overthrust that there are no significant foothills on the east side of the ,lewis ,range4 ,the fault has brought into direct contact the massive and resistant ,belt rocks which stand up as mountains1 and the relatively weak shales of the plains which are carved into subdued landscape features by erosion4 ,illustration3 ,,lewis ,,overthrust ,,at ,,base ,,of ,,mt4 ,,wynn ,,seen ,,from ,,highway ,,east ,,of ,,many ,,glacier ,,hotel4 ,,overthrust ,,lies ,,at ,,base ,,of ,,cliff4 ,,cretaceous ,,rocks ,,outcrop ,,on ,,gentle ,,slope ,,below ,,thrust4 7,,dyson ,,photo7 ,after the ,lewis overthrust had taken place1 and probably following a period of erosion1 the western part of the block broke along a vertical fault and sank several thousand feet4 ,for a short period of time a lake1 in which clay was deposited1 covered the floor of this depressed area4 ,the present valley of the ,north ,fork of the ,flathead ,river lies on this downfaulted block 7,figure #c;,d71 and the western boundary of the ,livingstone ,range marks the trace of the fault4 ,because the fault is of the high-angle variety the front of this range is much straighter than that of the ,lewis ,range which is formed by the notched eastern edge of the relatively thin overthrust block4 ,the ,belton ,hills and ,apgar ,mountains near the park's west entrance are isolated blocks separated from the ,livingstone ,range by normal faults probably dating from the time the ,north ,fork ,valley subsided4 ,the ,effect of the ,ice ,age ,in ,miocene and ,pliocene time the mountains were deeply eroded by streams4 ,it was during this time that ,chief ,mountain1 ,divide ,peak1 and two smaller outliers1 and the fenster along ,debris ,creek were formed4 ,all of the existing mountain valleys were cut out of the overthrust block1 although not to as great a depth as they have today4 ,the time required for their formation amounted to several millions of years4 ,the result of all this erosion was a landscape very similar to the present day ,blue ,ridge in ,virginia and ,north ,carolina1 the type which geologists call mature4 ,near the close of ,pliocene time the climate cooled1 timberline began to lower1 and increasing amounts of permanent snow accumulated in the higher parts of the mountains4 ,finally glaciers formed from the snow and began to move down the stream-carved valleys4 ,this marked the advent of ,pleistocene time 7,the ,glacial ,age7 nearly a million years ago4 ,glaciers eventually filled all valleys and covered all the park area except the summits of the highest peaks4 ,glaciers extended from valleys on the east side of the ,lewis ,range far out onto the plains1 and from the ,livingstone ,range and the west side of the ,lewis ,range they moved into the wide ,flathead ,valley4 ,the forests disappeared and it is probable that not a single tree remained in the area which is now the park4 ,available evidence indicates that climatic fluctuations during ,pleistocene time caused the glaciers to disappear for a considerable period of time1 or at least to shrink to insignificant size and then to return4 ,at the end of ,pleistocene time they began to shrink and about #i1jjj years ago1 during what is generally regarded as post-,pleistocene time1 disappeared again4 ,the large ,pleistocene glaciers greatly altered the pre-existing landscape of the park by gouging out valleys to much greater depth1 and making their sides and heads much steeper than the streams had been able to cut them4 ,most of the lakes1 vertical cliffs1 sharp peaks1 and waterfalls which constitute much of the park's magnificent scenery were created as a result of intensive glacier action4#d ,the ,last ,chapter ,although events of the last #i1jjj or so years didn't create the large spectacular features of the landscape1 this period is nonetheless interesting because it witnessed the birth of all existing park glaciers and the return of the trees composing the present-day forests4 ,as soon as the glaciers began to shrink trees undoubtedly started to reclothe the newly exposed surfaces4 ,new varieties came from areas which had not been glaciated4 ,from the ,pacific coast came grand fir1 ,douglas fir1 larch1 hemlock1 white pine and others4 ,from the east came another group including aspen1 paper birch1 hawthorn and maple4 ,the native trees driven out by the ice also returned to again become important elements of the flora4 ,these are ,engelmann spruce1 alpine fir1 and lodgepole pine4 ,a few species1 among which are the alpine willows1 driven southward from the far north during the ,pleistocene period still persist at high altitudes but they are always ready to move down into the valleys if the climate should again become cool4 ,of course1 continued warming would cause them to disappear4 ,after the large ,pleistocene streams of ice disappeared there followed a period of about #e1jjj years during which the climate was somewhat warmer and drier than at present1 conditions under which even very small glaciers could not have survived4 ,then about #d1jjj years ago the advent of the cooler climate brought about the origin of the present glaciers4 ,during the period of their existence they have fluctuated in size1 probably attaining maximum dimensions around the middle of the last century4 ,since then they have been steadily shrinking1 a sure indication that the climate is becoming milder1 as it has so many times in the past4 ,illustration3 ,,mount ,,jackson1 ,,visible ,,from ,,going-,,to-,,the-,,sun ,,highway1 ,,is ,,composed ,,of ,,steeply ,,tilted ,,strata ,,of ,,the ,,siyeh ,,formation4 ,,jackson ,,glacier ,,to ,,the ,,left ,,of ,,the ,,mountain ,,lies ,,on ,,the ,,surfaces ,,of ,,several ,,of ,,these ,,strata4 7,,dyson ,,photo7 ,surrounding all these small glaciers are recent moraines composed of rock debris eroded from the basins in which glaciers lie4 ,these moraines thus represent the amount of material removed1 and then deposited1 within the last #d1jjj years4 ,they are particularly striking at ,grinnell and ,sperry ,glaciers and at the site of the former ,clements ,glacier near ,logan ,pass4 ,illustration3 ,,moraine ,,near ,,grinnell ,,glacier ,,is #abj ,,feet ,,high4 7,,dyson ,,photo7 ,following disappearance of the large ,pleistocene glaciers streams returned to the valleys and began to cut new valleys within the old4 ,because post-,pleistocene time has been of such short duration these new valleys are small youthful gorges4 ,interesting examples are ,sunrift ,gorge1 where ,baring ,creek has cut a narrow channel into the upper part of the ,appekunny formation2 and the gorge at ,hidden ,falls on ,hidden ,creek in the ,grinnell ,valley4 ,sunrift ,gorge lies only a few feet north of ,going-to-the-,sun ,highway at ,baring ,creek bridge1 and ,hidden ,gorge is a stop on the guided trip which ,ranger-,naturalists conduct from ,many ,glacier ,hotel to ,grinnell ,lake4 ,both of these channels have very smooth1 straight sides because they have been eroded along vertical fractures known as joints4 ,the latter are common throughout the mountains and are responsible for the smooth surfaces on some of the highest cliffs4 ,the gorge of ,avalanche ,creek near ,avalanche ,campground is another example of post-glacial stream erosion1 only here the whirling action of sand and gravel-laden water has carved out a number of cylindrical potholes in the stream course4 ,some of them1 though only #f to #aj feet across1 are #bj or more feet deep4 ,since we know that the streams did not begin to cut these gorges until the large ,pleistocene glaciers had disappeared from those sites1 approximately #aj1jjj years have been required for their formation4 ,thus the average maximum rate of down-cutting has been of the magnitude of #j4jjb to #j4jjc inch per year4 ,with these figures as a foundation it is not so difficult to comprehend that the much larger valleys of the park could not have been eroded in less than several millions of years4 ,another common1 though seldom noticed1 post-glacial feature of the park is the alluvial fan4 ,these are fan-shaped accumulations of gravel deposited by swift1 tributary streams where they enter a main valley4 ,some of them have grown so large as to dam the stream in the major valley and cause a lake 7,figure #b74 ,st4 ,mary1 ,lower ,st4 ,mary1 ,lower ,two ,medicine1 and ,waterton ,lakes are held in by such dams4 ,the alluvial fan of ,divide ,creek which holds in ,st4 ,mary ,lake can easily be distinguished from ,going-to-the-,sun ,highway on the north side of the lake near its outlet4 ,the ,st4 ,mary ,entrance ,station is located on this fan4 ,the lower lake is dammed by a large fan built into the ,st4 ,mary ,valley by ,swiftcurrent ,creek4 ,the straight section of highway between the town of ,babb and the ,st4 ,mary ,river bridge lies on the lower part of this fan4 ,inasmuch as the ,pleistocene glaciers undoubtedly removed any such fans made previously1 those which are present today must have been constructed since disappearance of the ice1 and are then not more than #ab1jjj years old4 ,most of them are somewhat older1 possibly by as much as two or three thousand years1 than the gorges mentioned above1 because the latter are located nearer the source of the glaciers1 and their sites were thus still covered by ice after the fans had already begun to form4 ,after the ,pleistocene glaciers began their final retreat several thousand years elapsed before they disappeared from the mountains4 ,illustration3 ,,front ,,of ,,lewis ,,range1 ,,north ,,side ,,of ,,swiftcurrent ,,valley4 ,,the ,,lewis ,,overthrust ,,lies ,,at ,,the ,,base ,,of ,,the ,,cliff4 ,,three ,,large ,,talus ,,cones ,,are ,,visible ,,below ,,mt4 ,,altyn ,,on ,,the ,,left4 7,,dyson ,,photo7 ,one of the most conspicuous of all post-glacial features is the talus cone1 an accumulation of angular rock fragments which fall from cliffs4 ,it is only at the base of a crevice or chimney that this material takes the apparent form of a distinct cone4 ,elsewhere it is referred to as a talus slope or simply as talus1 or1 in the parlance of some mountaineers1 as scree4 ,although several thousand years have been required for their formation most talus accumulations in the park are still actively growing1 especially in spring and early summer when rocks are pried loose by the alternate freezing and thawing of moisture within fractures4 ,the artillery-like crack made when a falling rock crashes to the base of a high cliff is a familiar sound to anyone who has spent much time in the mountains4 ,the ,future ,we know that the processes of erosion and weathering will continue1 that alluvial fans and talus cones will grow larger1 and gorges will be eroded deeper1 and as a result the mountains will be cut down to lower elevations4 ,but1 as we have seen1 this event will require much time4 ,if the present climate continues for a few more years our remaining glaciers will disappear1 but there is nothing in geologic history which says they won't return again1 possibly even to the size of their heyday in the ,pleistocene4 ,and if history repeats itself1 and all past geologic history has been a repetition1 then the mountains will eventually be worn down to an uneventful plain and the sea will invade the land again4 ,but certain breeds of man are the only despoilers of mountains that we need fear1 so if the good citizens of our land keep the human invader and his dams and earth-moving equipment out of our national parks these grand mountains will endure for many thousands1 yes1 even millions of years4 ,footnotes #a;,dr4 ,dyson worked as a ranger-naturalist in ,glacier ,national ,park for eight summers starting in #aice4 #b;,argillite is the term used by geologists for a rock1 originally a shale1 which has been recrystallized or made harder by greater pressure4 ,in external appearance it looks like shale4 #c;,a dike is like a sill in all respects except that it cuts across adjacent layers instead of paralleling them4 #d;,for a complete discussion of glaciers and their effects see ,special ,bulletin ,no4 #b 7,glaciers and ,glaciation in ,glacier ,national ,park7 of the ,glacier ,natural ,history ,association4 ,,printed ,,in ,u4 ,s4 ,a4 ,,by ,,glacier ,,natural ,,history ,,association ,,in ,,cooperation ,,with ,,national ,,park ,,service ,,department ,,of ,,interior #aiec ,o',,neil ,,printers--,,kalispell1 ,,montana ,principal ,aims of the ,,glacier ,,natural ,,history ,,association1 ,inc4 ,glacier ,national ,park ,west ,glacier1 ,montana ,organized for the purpose of cooperating with the ,national ,park ,service by assisting the ,naturalist ,department of ,glacier ,national ,park in the development of a broad public understanding of the geology1 plant and animal life1 history1 ,indians and related subjects bearing on the park region4 ,it aids in the development of the ,glacier ,national ,park museum library1 museums and wayside exhibits2 offers books on natural history pertaining to this area for sale to the public2 assists in the acquisition of non-federally owned lands within the park in behalf of the ,united ,states government2 and cooperates with government projects in the completion and development of ,glacier ,national ,park as needed4 ,revenue derived from the activities of the ,glacier ,natural ,history ,association is devoted entirely to the purposes outlined4 ,any person interested in the furtherance of these purposes may become a member upon payment of the annual fee of one dollar4 ,gifts and donations are accepted for land acquisition or general use4 ,bulletin ,no4 #a--,motorists ,guide to the ,going-to-the-,sun ,highway1 #aidg--,price #be ,cents4 ,bulletin ,no4 #b--;,glaciers and ,glaciation in ,glacier ,national ,park1 #aidh--,price #be ,cents4 ,bulletin ,no4 #c--;,geologic ,story of ,glacier ,national ,park1 #aidi--,price #be ,cents4 ,bulletin ,no4 #d--,trees and ,forests of ,glacier ,national ,park1 #aiej--,price #ej ,cents4 ,bulletin ,no4 #e--aja ,wildflowers of ,glacier ,national ,park1 #aieb--,price #ej ,cents4 ,transcriber's ,notes --,copyright notice provided as in the original--this e-text is public domain in the country of publication4 --,silently corrected palpable typos1 leaving non-standard spellings and dialect unchanged4 --,only in the text versions1 delimited italicized text 7or non-italicized text within poetry7 in underscores 7the ,,html version reproduces the font form of the printed book47