Lit. 461 Cornell University Library The original of this book is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924004873190 "PLim Count «e^ >v,th Jish Bf^ /y^e** o^m..ni-«r,< SOME VOLCANIC ASH BEDS M O X T A 1ST A Jesse Perry Rowe, M. A., \ . Professor of Physics and Geology UNIVERSITY OF MONTANA HELENA, MONTANA INDEPENDENT PUBLISHING COMPANY 1903 CONTENTS Introduction. Theory of Origin. Physical Properties. Chemical Composition. Economic Importance. Distribution of Beds in Montana. COUNTIES WITH ASH BEDS 1— Beaverhead. 2— Broadwater. 3— Cascade. 4HDeer Lodge. 5— Fergus. 6— Gallatin. 7— Granite. 8— Jefferson. 9— Madison. 10— Meagher. 11— 'Missoula. 12— Park. 13— 'Powell. 14-jRavalIi. 15— Silver Bow. 16— Lewis and Clarke. Acknowledgment. The writer is greatly indebted to Mrs. Sue Lewis-Thompson Univ. of Montana, '01, for her valuable assistance in the arrange- ment of this paper and the microscopic plates. Also to Mr. Oral J. Berry, an advanced student in chemistry, for his careful arid painstaking analysis of the Ravalli County Ash, and to Professor E. H. Barbour, University of Nebraska, for his many valuable suggestions and bibliography on this subject. Some Montana Volcanic Ash Deposits Introduction. Montana, located between the forty-fifth and forty-ninth de- grees north latitude, and the one hundred and fourth and the one hundred and sixteenth degrees west longitude, comprising about 146,000 square miles or 93,000,000 acres of territory is probably one of the best states, geologically speaking, in the union,- com- prising as it does, the entire geological gamut from Azoic to the present. , As its mountains are comparatively new in their formation, the rivers are quite straight and their banks steep, and the moun- tains are precipitous and rugged, showing a lack of wear and. tear of the agents of disintegration, as is shown in the older Appalach- ian system. Montana was also the home of many, now extinct, violent volcanoes. ■ Evidence of this may readily be seen in many parts of the state, in the shape of warm springs, hot sulphur springs, various acidic volcanic rocks and last but not least, numerous beds of valconic ash, found in almost every county of the state. The natural resources of the State, aside from gold, silver and copper, are not being developed very rapidly. In .mineralogy, lithology, palaeontology > and physiography, the United States Geological Survey has done most of the work of this kind in the state. Some work of minor importance has been done by individuals, and the University of Montana, in the summer of 1900 and 1902, made some good col- lections of fossils and rocks ; but the vast portion of the state is yet untouched along these lines. It is the writer's purpose in. this paper to study, not in detail, but quite carefully, the volcanic ash beds or deposits of various counties in the state, giving his theory of their probable formar tion, their extent, their position in the geological time scale- and some of the uses, to which they are now put and their future economic value. These few pages are to serve but as a nucleus around which years of future investigation will build a structure of Montana's geology. Throughout the entire earth, where the mind of man has studied and investigated its formations, volcanic evidences are more or less numerous. While volcanoes do not occur every- where, there are certain violent eruptive ones that send forth into the upper currents of air, their cinders, steam and finer par- ticles, many hundreds of feet, which by the action of these cur- rents, carry the finer material many miles from the seat of activ- ity — either seaward to deposit on the floor of the ocean or over portions far inland and thereby depositing in land locked seas or on the hills and valleys ; afterward to be washed into the lakes by meansj>£.*fee various streams passing through the country. Theory of Origin. In accounting for the origin ., of volcanic ash, we might best use Daubree's hydrothermal fusion theory. For when rocks containing water are subjected to great pressure they become liquid at about one-third the temperature for the normal fusion. Now by some sudden change or 'break in the earth's crust, by subsidence or other means, this pressure on the highly heated rock mass is quickly relieved, immediately steam is formed and by its sudden change of volume from water to wate'r vapor, the material, rock liquid is blown into the finest particles and thrown many hundreds of feet into the air, to settle, part of it, as volcanic ash in some remote quarter of the globe. Most of the ash deposits in Kansas, Nebraska and other cen- tral states are probably due to wind-blown material from the west in or about the Cretaceous period ; while that found depos- ited in Montana is almost entirely from local causes, either from the Yellowstone Park volcanoes, which were in erup- tion during the Neocene epoch, or from volcanoes, of different geological epochs, in the state. While some of the deposits may be from foreign eruptions, such as those of the Coast Range or Sierra Nevada, there is also a possibility of part, even coming from some of the oceanic is- lands, such as from the Sandwich Islands, etc. As an outburst Of Krakatoa but a few years ago, in the month of August, hurled these tiny volcanic fragments to the height of something like fif- — 7— teen or twenty miles, and so many of them that darkness pre- vailed in' mid-day to a distance of nearly two hundred miles from the crater, and that these particles encircled the globe and re- mained suspended in the air during the following winter and ■spring. It is also estimated that another recent volcano spread its ashes over an area of almost a million square miles. Some of the European countries have what they call "Ashies," inasmuch as the air is so thoroughly permeated with this fine material as to make the otherwise bright days, like an Indian summer, de- stroy crops and sometimes last for an entire season. Sometimes vessels in mid ocean are literally covered with this fine glassy material and instances are recorded where over a foot fell in a single dayi In 1872 Vesuvius erupted and; part of the outburst was steam and ash and from the description, resembled a* hrrgaisatqjtm .cloud rising in the distance. Most of the heavier material in such an eruption would deposit around or close to the crater, while the finer particles would be caught up by the upper currents of air and transported and deposited far from its origin. Thus we see that volcanic dust or ash may be found almost anywhere ; in the center of the great plains, on the waves in mid ocean, in the great deserts — everywhere, it leads an active life. First separated from its neighbors by internal heat, then thrown With violence from its community by the action of the pent up steam, only to be carried farther and farther away from kindreds and associated ; may be to be deposited in some fertile valley, on some lonely hill or beneath the rolling deep. Then to have other like or unlike particles piled upin it until its very existence is jnot recognized, until by, the same pressure, by the same causes that took it from its former home, it is again eons and eons hence, hurled into the air with great force and distance to seek another temporary resting place, none knows where. Physical and Chemical Properties. The color of the volcanic ash deposits as a whole is a whitish gray, but no two beds have exactly the same tint. Some are bluish gray, some light gray, some dark grey, while some are even slightly reddish, due undoubtedly to the presence of iron in the surrounding formations. It has a glistening, glimmering more or less vitreous lustre, and when spread out on the hand in the 'sunlight shows its glassy nature by reflecting the rays of light. It varies from very fine flour-like powder to quite coarse — 8— ' grains. Almost always found in layers of thin laminae or strati- fied; especially is this true in deposits found in old sea or lake beds. It has a specific gravity of 2.5 and the microscope reveals its real identity, showing it to be made up of a number of angular fragments, almost transparent and many pieces filled with small capillary tubes, due to its being in a viscous condition at one time and quickly blown into shreds by the escaping gas. The ash is recognized from diatomceous earth, which it very much resembles, in having a much higher specific gravity in the bulk. Dry diatomaceous earth will float for a while on water, but later becomes "logged" and sinks. Volcanic ash, however, will not float, but immediately sinks to the bottom. The ash is recognized from silt, which it also resembles, by its glistening properties as stated before and by the microscope. Here silt gives rounded particles while ash gives the angular. Volcanic ash is one of the best known preserves of nature's biologic specimens found. When mixed with water and steam from the volcano, it falls in the shape of mud and is called volcanic tuff, which, when falling on animals or plants or upon the handi- work of man, beautifully preserves them or holds their impression almost perfectly. This dust or ash is a very good non-conductor of heat, probably due to its being so fine grained and its low spe- cific gravity, and anything buried beneath it would be little ef- ected by subsequent flows of lava. Hence in these deposits, es- pecially those that have been formed in lakes or seas, we might expect and really do find many fossils, such as leaves, rodents and other beautifully preserved specimens. Chemically it has but few if any simple reactions or tests. It is not acted on by any of the common acids ; gives but a feeble soda flame ; yields a small amount of water in a closed tube ; gives a slight test for iron with potassium ferro cyanide and ammonium sulpho cyanate, and yields a skeleton silica bead with a phos- phorous salt. Another simple test is with cobalt nitrate, when the aluminum blue is given. Composition. The composition of the ash was carefully tested and found to be quite similar to that given by the United States Geological Survey Bulletin, No. 150, and by various other authorities. The composition varies, however, as all volcanic material of the same name but of different localities, have different compositions ; while — 9- the essentials are the same, the accessories would naturally vary. The chemical analysis of the ash from Ravalli County, was made in April, 1901, by Oral J. Berry, an advanced student in chemistry of the University of Montana and is as follows : Composition No: 1 Per Cent No. 2 Per Cent Ha O . . . . 2.IO 68.49 21.35 •39 3-487 4.169 2.12 Si Oi 68-54 21.27 , 4 6 345 4.15 AL* O3 -\- Fe; Oi Mg Naz O K* Total 99.986 99-99 Two careful analyses were- made marked here No. 1 and No. 2. The composition of the ash below given is from Gallatin Val- ley, Gallatin County, Montana. It is found in the Neocene lake bedi of this county of various thicknesses, probably washed in from the surrounding country. No. 1— Analysis of the Montana ash, just as found in the beds. No. 2Analysis of the Montana ash after ignition. The per cent of loss by ignition is left out. This per cent shows a highly hydrated ash. No. 3 — 'Analysis of a rhyolite from the North Madison Plateau, Yellowstone Park. Analyses of Volcanic Ash rom Gallatin County, Etc. 1 - ( Compounds Per Cent No. 1 Per Cent No. 2 Per Cent No. 3 SiO> 68.68 12.69 1. 14 1. 17 Trace 1. 14 1. 11 1.23 . 5-58 74-59 13-78 1.23 1.27 Trace 1.23 1:21 1-34 6.06 75-19 13.77 .61 AL2O3 Fe2 O3 FeO...' i-37 Trace MnO MgO .09 .68 CaO Na*0 K* O 3-83 3-33 .02 SO3 . .29 Ignition .... 7-99 .65 Total 100.73 100.71 S9-83 The above is taken from the U. S. G. S. Bulletin, No. 150, De- scription No. 58, pages 147-8. As a comparison between the composition of the older vol- canic ■ ash and that more recently erupted, we give below the analysis of volcanic dust or ash from La Soufriere, collected by Edmund Otis Hovey, May 27, 1902, and analyzed by Dr. W. F. Hillebrand of the U. S. G. S. Analysis of Volcanic Ash From La Soufriere. Composition Si Os AL* O3 Fe* Oj FeO.. : MgQ . Ca O Na*0 •. K*0.- tU O at ioo° C H* O above ioo° C Ti O* ZrO* CO* Per Cent 55.08 18.00 2.46- 4-57 3-34 7-74 3-45 0.65 0.66 i-39 0.80 (?) None Composition P*Os SO3 CI S (included in Fe7 Sb ) NiO MnO BaO •SrO LiO* FeySs (?). Total Per Cent O.I7 O.24 None 0.36 None- 0.21 Trace None Faint Trace O.9I 99.67 Economic Importance. Volcanic ash, while as yet has but little commercial value, is gradually coming to the front and in a few years the writer ex- pects it to be in demand and good use made of all the vast beds in the central and western states, Up to date it is used chiefly as an abrasive, or polishing purposes, being put up in neat pack- ages and sold as silver, polish, etc. It is also used in the manu- facturing of scouring soap. The N. P. and B. & M. railroads use a soap in their Pullman lavatories that contains material, micro- scopically identical, to the ash. It could not be learned, how- ever, whether it was the real ash or not: Another brand of soap similar to the former from a New York company was carefully examined and found to be the same. This firm was written to, but they claimed that nothing like ash (volcanic) was used in the manufacture of their soap. We believe it is either the ash or powdered pumice. Denver and Omaha use the material for making soap and, as in many places, it is easily accessible and close to a railroad, it can be had almost for the digging. There are several places in Nebraska where men have abandoned their farming and gone on the road to sell this material, and clear a neat sum each year from its sale. There is no reason why it should not be used with lime for plastering, making a very fiae grained plaster or better, a cement like surface. A man near Missoula, in Missoula County, contemplates mak- ing brick from the ash. As a matter of fact he has tried to burn 'some and thinks it will work splendidly and probably give to them a glaze, if sufficient heat can be obtained, and far excel and be fully as cheap as the now brick of commerce. There are various channels by which this material might come into commercial prominence, but so far none have been thor- oughly developed. It is also a well known fact that volcanic "debris" is a very good "crop soil," and wherever this dust has spread over a country or patch of land vegetataion is there very abundant and very rank. On the plains of Idaho, near the rail- road from Ogden, Utah, to California, the country in places is lit- erally covered with volcanic ash, and where water can be secured for irrigation, no better or more fertile soil can be found. How- ever, so slight is the annual precipitation in this locality, that where artificial means for watering the soil is not resorted to, it remains little less than a perfect desert. The soil near and around Salt Lake City and Ogden, Utah, contain a larger or smaller per cent of this ash and here where the annual rainfall is assisted by irrigation, no better place in the United States can be found for beautiful and almost tropical vegetable growth. This ash may then be used as a fertilizer and that, too, very profitably. In Beaverhead County, this state, the rock composed of vol- canic ash is considered their best and most durable buildingstone. There are large quarries and the rock, is easy to work, be- ing quite soft when first taken out, but upon exposure to the air for some time becomes very hard. Most of the best buildings in Dillon are constructed wholly or in part from this rock. Beds in Montana. Montana has had various epochs of volcanic activity and from the evidence remaining they occurred in more than one geolog- ical period and were quite active at each appearance. Probably one of the -most active times was during the Tertiary period, a — 12 — ' time also characterized in Montana, especially the western part, by fresh water Neocene lakes. Also during this period our neigh- boring state, Wyoming, the Yellowstone Park region, was vol- canically active, and from these and the local vents, most or all of the ash has originated. Some of the Yellowstone ash was gathered by the winds, as was also the Montana ashj and blown directly into the lakes and sank to the bottom as pure ash ; other fell on ;the land and was washed into the lakes and deposited with other erosive material, and is therefore interbedded with sand or clay. In almost every Neocene lake bed the presence of ash has been found. In the study of the beds here, the writer has not been able to visit each bed and make exact measurements, but several coun- ties have been visited and their deposits and the formations care- fully studied. Museum specimens have been freely used in com- paring the color, texture, etc., and student visits and descriptions have been occasionally used ; also some information gathered from the United States Geological Survey. Folios and other sources. The work is as yet very incomplete, but affords a nu- cleus for future investigation. We fully expect to find the ash in all or nearly all of the coun- ties of the state, and within another year it is our desire to have visited the remaining unworked counties and ascertain to some degree the geological formations and find other beds of this ma- terial. The counties represented in this paper, and those which will have more or less of a description of their beds are given as fol- lows: Counties. 1— Beaverhead County. 9— Madison County. 2— Broadwater County. 10— Meagher County. 3— Cascade County. 11— Missoula County. 4— 'Deer Lodge County. 12— Park County. 5— (Fergus County. 13— Powell County. 6-^Gallatin County. 14— Ravalli County. 7-^Grranite County. 16— Silver Bow County. 8-Jefferson County. 16— Lewis and Clarke County. These counties will be taken up in regular order and a brief de- scription of each given. Beaverhead County. This county is situated in the southwestern part of the state bordering the state of Idaho and crossed in the east by the Ore- ,.- — 13— gon Short Line railroad. Dillon is the largest city and county- seat and also the home of the Montana State Normal. In this county we were able to obtain but small specimens of ash and volcanic tuff. The ash here is usually of a grayish color Ash from Beaverhead Cottnty, Montana. and varies from fine to coarse, but almost entirely free from foreign material. The deposits probably come from the Yel- lowstone volcanoes or from the Ruby mountains east of this county, which was at one time the scene of volcanic activity. Large compact samples were on exhibition at Butte from this county during the International Mining Congress, with a state- ment that it was used there as a building stone. The samples were quite hard and had a very Uniform texture. From recent information from Professor J. E. Tyree of Dillon, it is learned that the new County High School (Plate 9) has one story built from this material. The new Library, the State Normal Dor- mitory foundation and several of the- most handsome and sub- stantial buildings and residences in that city are made from this ash building stone. The outcrop -and quarries are located in the Frying Pan Basin, about eight miles (N. W.) from Dillon and two and one-half miles from the Oregon Short Line Railroad. The bed is about a mile long, one-half mile wide and from forty to sixty feet in thickness. It is capped by a hard rhyolitic lithoe- —14— dite rock and in the lower ash are often found pieces of petrified stumps and trees. Broadwater County; Broadwater County, one of the smallest in the state,, lies be- tween the in degree and 112 degree West Longitude and the 46 degree and 47 degree North Latitude. It is bounded on the northeast by the Big Belt mountains and diagonally cut by the Northern Pacific railroad. Townsend is the largest city and county seat and located in the central part of the county. We have no specimens from this county, but in the Three Forks Folio of the U. S. G. S. it is mentioned as having several large deposits and these being found in the Neocene lake beds. Cascade County. Cascade County, almost the central part of the state, is cut by the 1 nth meridian west, and the 47th parallel north. Crossed diagonally from southwest to northeast by the Missouri river; bounded on the south and east by the Little Belt mountains; on the south and west by the Big Belt mountains, and on the northeast corner by the Highwood mountains, having Great Falls as its largest city and county seat. In this county, south of the Highwood mountains, on Byrnes' Creek, in the Colorado Cretaceous, are found several outcrops of the ash. They occur . -between, beds, of sandstone and have an altitude of 4,000 feet! The ash here is quite white in color and appears more or less stratified. Some of the beds are quite thick while others along the creek are mere pockets. These deposits were probably due to the violent eruption of the Highwood mountains, which have an altitude of about 7,500 feet, and from all evidence were once the seat of very violent vol- canic activity. As proof of this, all or nearly all of the rocks in this vicinity are of undoubted volcanic origin ; both extrusive, as the andesites and the basaltic breccias, and the intrusive as basal- tic dykes, syenites and porphyrys. Most of the Highwood moun- tains are in Chouteau County and probably belong to the Eocene epoch. Deer Lodge County. Deer Lodge County, the smallest county in the state, directly north of Silver Bow County, has for its county seat and largest city the famous Daly smelting camp, Anaconda. —15— The deposits of ash in this county are found all along Silver Bow Creek from Butte to Garrison and also near Anaconda. None of these beds have ever been measured, but have been seen ■•a^d^pTftt«Ttarily3*visited, during, the ; stop of trains -at star tions and their identity fully established. We have no museum specimens or microscopic slides, but have passed the deposits many times and therefore thoroughly familiar with their char- acter and locality. Fergus County. Fergus County; the most centrally located of all the counties, with Lewistown, sixty miles from a railroad and almost the geo- graphical center of the state, as its county seat and largest city. This county has within its borders the Big Snowy mountains, the Little Snowy mountains and many others of minor import- ance. Bounded on the north by the Missouri and on the east by the Musselshell rivers. The south and west corner contains the famous Yogo Gulch, with its Yogo Sapphire mines, and on the southwest is situated the Little Belt" mountains. Here, as in Cascade County, the ash deposits are found in the Colorado Cretaceous, south and east of the Highwood ' moun- tains on Arrow Creek, directly west of the deposits in Cascade County. Sandstone of varying thickness; ash of varying thickness; sandstone of varying thickness. The above is a cross section of the ash beds in Fergus and Cascade Counties, showing the beds of sandstone above and be- low the ash. It is now reported that this county has. ash that yields $i to $2.10 in gold per ton. Gallatin County. This county lies in the southern part of the state bordering the Yellowstone Park. It is crossed by the Northern Pacific Rail- road and the 46th parallel and the iuth degree meridian west. Its longest axis runs north and south and has Bozeman as its largest city and county seat. Bozeman is in the central part of the county and is the seat, of the Montana College of Agriculture and Mechanic Arts. The ash beds here are doubtless the best and largest in the —16- state. The deposit that is pure probably fell directly into the water from the, volcano and is not more than fifteen or twenty feet thick. Above this pure homogenous ash there are impure beds of varying thickness, ranging from ioo to 1,000 feet thick. These upper beds are formed almost entirely from erosion and are composed of a mixture of sand and ash. The best exposures or beds of ash in this county are in the Figs. A and B— Ash from Gallatin County, Montana. Gallatin Valley, where the pure ash is in layers of about five feet thick, between layers of impure ash. In the northern part of this —17— valley the layers of strata of pure ash are from two to five feet thick and are separated by thin calcareous strata. These riiixed beds are about twenty feet in thickness. In the lower part 01 this valley many good, pure, but coarse beds of ash are found. This ash varies somewhat both in color and texture. This county, especially in the valleys, is literally covered with these ash beds, some coarse, some fine, from pure -direct deposits to impure, mixed, eroded deposits, all make up a vast territory of ash. Granite County. This county is located in the southwestern part of the state, with Phillipsburg* as its chief town and county seat. In this county many fine deposits are found, especially in the Hellgate Valley, as here are found immense deposits of impure ash. The valley has been made almost entirely, if not wholly, from ero- Ash from Hellgate Valley, Granite County, Montana. sion and on each side of the valley are many fine ash outcrops. The beds vary in thickness, but none are greater than a few feet. In many places the ash beds are covered to a thickness of four or five feet with dark loam, mostly from plant decomposition. Several of these 'beds have had the roof of loam washed off, thereby leaving beautiful expoures of the ash. Almost all the -beds found here are of the loose kind. Most of the deposits elsewhere are more or less consolidated. The ash here contains lime, sand and clay particles, and efferveses — 18— quite freely when hydrochloric acid is applied to it. Other beds of pure but coarse ash are found at New Chicago and along Dunkelberg Creek. At these places the ash is more coherent than at the others and has a bluish white color. It contains lit- tle if any foreign material. In a rock specimen from the beds near New Chicago a fossil fish was found imbedded in a matrix of clay containing diatoms Q Ash from Dunkelburg Break, Granite County, Montana. and a small percentage of volcanic ash.. About two or three miles up the river from Drummond are some very fine outcrops of ash and clay. The ash lies as a cap for the clay beds and measures from two to ten feet in thickness. The ash is quite pure, but coarse and compact. It lies from one to two hundred feet above the valley and its outcrops extend for more than a mile up the river on the left of the wagon and railroad grades. Jefferson County. This county is in the west south central part of the state with Boulder as its largest city. No specimens have been obtained, nor visits made to the Jef- ferson ash beds, but in the Three Forks Folio of the United States Geological Survey they are mentioned as forming an im- —19— portant part of the Neocene Lake beds, not only in this, but in Broadwater, Gallatin and Madison Counties. This is more evidence of what has already been said, that wherever Neocene lake beds are found, there ash deposits will also be found. Madison County. This county is situated in the southern part of the state, west of Gallatin County, which borders the Yellowstone Park. In the north of this county is located the South Boulder mountains ; in the east the Madison range; in the south the Tobacco Root range and the Snow Crest range, and in the west the Ruby mountains. The last, or the Ruby mountains, were ,at- one time very active volcanically. Virginia City is the county seat and with Twin Bridges are the two largest cities. The ash beds in this county, like those in Gallatin county, are composed of layers of quite pure ash, Covered by layers of very impure ash. As stated before, the pure ash beds were probably formed from ptire ash falling directly into the lakes or seas, while the impure is naturally a later deposit, as it is found cap- ping the pure and has been formed from erosion or has been washed into the lakes or seas from the surrounding land deposits. From what can be learned from the form of these beds, it seems that the ones in the eastern part, especially in the Upper Madison valley, must have been deposited at the same time, and perhaps in the same body of water as those in Gallatin County. The specimens from Ruby Creek, in the southern part of Mad- ison Valley, contain a great deal of organic and other foreign matter. See PI. II A. Mr. Earl Douglas, who has spent several years studying the lake bed deposits of Western Montana, states that along the Black Tailed Deer Creek, in Madison and Beaverhead, Counties, there is a deposit of ash from seventy to eighty feet thick. This ash is weathered in a very peculiar manner. Along the slopes are pillars and towers resembling, from a distance, beautiful marble temples. Meagher County. This county is located in the central part of the state, with White Sulphur Springs (so named on account of the hot sulphur 20 springs in and around the town) as its largest city and county- seat. The county contains many mountains wthin its borders and also many very fertile valleys. The Musselshell Valley in the east and south and the Smith River Valley from White- Sul- phur Springs south, are among the best known sections of the county. In this county the Castle mountains was one of the chief sources of volcanic activity. It probably covered a single period of eruption and occurred just before, or during the Neocene epoch. In speaking of the ash deposits from Castle mountain the U. S. G. S, says: "Rhyolitic tuffs or ash beds, resulting from ash showers of the old volcano are more or less abundant over the whole district." Some places on Checkerboard Creek the expos- ures range from thirty to fifty feet in thickness. Here probably some iron enters into the composition, as the color is not as white as in other surrounding countes, but somewhat of a light brownish red and faintly stratified. East of Copperopolis, where the streams or creeks have eroded through the upper igneous rocks, very good beds of this ash are exposed. Near White Sul- phur Springs and all down the Smith River Valley are found beautiful beds of this material, undoubtedly washed into this Neocene lake bed from the surrounding country. ^ Castle mountain, the probable source of all the ash found in and around this county, has as its highest peak or elevation Elk peak, which is 8,600 feet above sea level. It. is located south and east of White Sulphur Springs (which has an elevation of 5,000 feet) and south and west of Copperopolis This county was visited during the past summer and several proofs of its belonging to the Tertiary period were found. An extinct volcano was visited, being located about fifteen miles from White Sulphur Springs by wagon road or five or six miles by air line. This volcano had its crater filled with highly vesicular lava and in much of the lower lava, amydalloidal formation was very prominent. The crater is about 150 ' to 200 feet across and the center is probably 25 to 50 feet lower than the sides. Vesic- ular lava similar to that found ( in the Crater is found five or six miles from the volcano on almost as high hills as itself. This was probably an explosive type of volcano and undoubtedly fur- — 21 — nished some of the ash that is now found in the Smith River Val- ley. Missoula County. Missoula County, located in the west central part of Montana, is one of the largest and best counties in the state. Missoula is the county seat and largest city and the home of the State Uni- versity. This county is entered by the two rivers, Hellgate or Missoula River and the Bitter Root River. These join in this county a lit- tle below Fort Missoula, helping to form the Claries' fork of the Columbia. In and around xvxissoula Valley are found many large and char- acteristic deposits of this volcanic ash. The bed or beds, as there were several found, in partcular are north of Missoula City. They are from 400 to 600 feet above the level of the valley, which is about 3,100 feet above sea level, and extend along the hillsile for several miles. Outcrops, are seen in every'gUlly and ravine and in many places along the surface of the land. Nowhere does it seem to be covered with more than a foot or more of loam, and in many places it gives to the soil a peculiar whitish color that can be distinguished sometimes for miles away. These beds are of a very pure quality of ash and are very dis- tinctly stratified. The ash breaks readily along the bedding planes, especially after it has been exposed to the weather and dried out for a short 1;ime, then it shales off in beautiful thin sheets, resembling very, much the cleavage of slate. Here joint- ing was also observed ; jointing in two ways. Some of the beds are as hard as the compact limestone rock, while others are com- paratively soft and friable. Probably the most interesting feature of these deposits is their richness in, fossil leaves. Some of these leaves have been exam- ined by the U. S. G. S. and are probably Neocene. s The following are some of the species determined : 1 — Sequoia longsdorfi. 2 — Sequoia (Probably new species.) 3 — Glyplostrobus Europeans. 4 — Alnus . 5— Carpinus (Probably new species.) 6 — Cornusor Viburnum. 7 — Populus balsomoides (?) — 22 — 8 — Fruit near Chincnonidium. 9 — Taxodium occidentalis. io — Taxodium. The writer is preparing a separate paper on these leaves. Most of these leaves are very beautifully preserved. They are of a light brown color in a matrix of white ash. Most of them are found about six feet below the surface of the ground, but in some of the beds they are found much nearer. For a considerable depth the ash is fissured and the crevasses are filled with tiny rootlets and other living organic material. These beds, like some others in the state, are deeply colored with iron. It is noticeable that the leaves occur in whitish vm L.A Y,A (JUM^U- S«JL(lM.t-^ of <^- (X*-A- -■^-'-d- -"*-• Wlrtyefj™-^*- Off- L f layers, though the layers immediately above and beneath them are deeply stained with iron. A well has been dug in the hillside through the ash beds in which it was found that the layer of ash is thirty-five feet thick. —23— For some distance above and below this well outcrops of the ash were found, so that the depth of the entire deposit could not be accurately determined. The highest outcrop of ash was found at an altitude of 3,850 feet and the lowest 3,650 feet. Though even below this latter ■G\/f%Xb-r3ji-ZAAJ^^\. ;tj£\/^t ytf^uoTsJ.^ & 4 £*X $■* some ash was found, but had been undoubtedly washed down from the upper beds. If we could prove these outcrops to be one continuous bed the deposit would be over 200 feet thick. It is, however, probably several different deposits and other material will be found between each bed. —2 4 — Park County. Park County, located in the southern part of the state and bounding the Yellowstone National Park on the north, has Gal- latin County as a western and Sweetgrass County as an eastern boundary, with Meagher County at its north. It is crossed by the Northern Pacific railroad and Livingston is its largest city and county seat. The county ,is crossed by the Yellowstone River, and has the Snowy mountains almost en- tirely covering its western portion. In the Livingston Folio of the U. S. G. S. volcanic ash beds are mentioned as occurring within the confines of this county and most undoubtedly in the Neocene lake beds. Also Andesitic breccias and tuffs are found here, showing the presence at one time of a near by violent erupting volcano. In many places along the Yellowstone River these deposits are found, especially where the Neocene lake beds are exposed, but so great has been the erosion that very little of the deposits remain. It seems that in most parts of Park County these lake deposits are covered by later flows of Andesitic breccias. Powell County. Powell County, recently created from Deer Lodge County, is in the West central part of the state with Deer Lodge as its county seat and largest city. This county, has never been visited personally except at Gar- B. Ash from Powell County. Montana, rison, where a small amount of ash was found along the creek —25— bank. This presumably came from the deposits in Deer Lodge and Silver Bow Counties. We are in possession of a specimen from the, White River beds from below Helmville,'and it is a very poor or impure ash, containing besides the small non-vesicular ash fragments, con- siderable organic matter, together with clay and a few diatoms. ' Ravalli County. Ravalli County is on the western border of the state, with Hamilton as its largest city and county seat. This county has running through it from south to north the Bitter Root river, on whose banks border the famous Bitter Root Valley, noted for its beautiful homes and profitable orchards. The ash beds in this county were visited and are among the best in the state. They are mostly located in the Bitter Root Valley and the largest are found near Victor, a ten mile drive from Hamilton, on the east side of the valley and along the foot- hills. The best outcrop visited is where a mountain stream has done a vast amount of eroding and a bank of seventy feet high , (from the center of the small creek below) is exposed. The first forty feet of this bluff is composed of clay. Above this is a layer of coarse but compact ash, about eight feet in thickness, and immediately above this is a layer from two to four feet of very pure, fine ash. The remainng eighteen or twenty feet is clay, gravel and volcanic rocks. Scattered through the layers of ash are some very beautiful but peculiar concretionary structures. These concretions are of two kinds. The first kind are noduls of common quartz and mica sand, with a calcareous cement, containing very little if any of the ash in its interior make up. The second kind are com- posed of very pure ash cemented with calcareous material. In order to prove conclusively -their internal make up, they were carefully washed and dried, after which the outer portion was removed and the inner part crushed and subjected to Sul- phuric acid, to remove of char any organic matter, decanted, washed, dried and then put into Hydrochloric acid to remove any calcareous material that might remain. It was again washed and dried after which it was put under a microscope and found to be almost pure ash with a few siliceous diatoms. As is u$ual, , with certain kinds of concretions, these have more -26— or less of a concentric structure and many of them nearly spherical in form. The most common form is where several little fP^&^*ff$*?W*~*M: &. 7- -. H. Barbour; Notes on the Ash Beds of Nebraska and the Great Plains. Mineral Industry, Vol. 6, 1898, pages 22 to 27, 5 figures. 19. E. H. Barbour. Volcanic Ash in Nebraska soils. Report of State Geolog- H\, pages 239-241. 20. The Present Paper. , — 3 o— PLATE II. Ash from Ruby Creek, Madison County. PLATE III. Ash from Ravalli County, near Corvallis. PLATE IV. Ash from Ravalli County, near Stevensville- —32- PLATE V. PLATE VII. Leaves from Volcanic Ash, Missoula County. PLATE VIII. PLATE IX. . 2 "I s c o < o H p.