GEOLOGICAL SUEYEY OF THE TEEEITORIES. 173 



and is about sixty miles long. It is well watered by tbe brancbes of 

 tbe Gallatin Eiver, wbicb are extensively used in irrigation. Tbe bills 

 are covered witb excellent grass, and form one of tbe best grazing 

 grounds in tbe world. Quite a considerable part of tbe valley is already 

 under cultivation. Crossing tbe Gallatin, we soon arrived at Bozeman 

 City, a flourisbing town, destined to be of considerable importance 

 sbould tbe Nortbern Pacific Eailroad run tbrougb it. Tbree miles be- 

 yond tbe town we pitcbed our tents at Fort Ellis. Fort Ellis is situated 

 on tbe eastern side of tbe Gallatin Valley, on tbe east brancb of tbe Gal- 

 latin Eiver, and bas a force of four companies of cavalry and one com- 

 pany of infantry, under tbe command of Major E. M. Baker. On tbe 

 lltb of July we visited a small lake twelve miles soutbeast of tbe fort. 

 After a ride over a trail wbicb led tbrougb dense timber, making our 

 progress difficult, we reacbed tbe lake, a beautiful sbeet of water en- 

 sconsed in tbe midst of bills wbicb rise to a considerable beigbt around 

 it. It is about balf a mile in widtb, and tbe stream flowing from it 

 forces its way in a deep gully tbrougb quartzites. It falls about 500 

 feet in a quarter of a mile. It rusbes along witb furious rapidity, leav- 

 ing bigb projections of rock on eitber side. Tbe lake sbore is bordered 

 witb limestones, wbicb rest on tbe quartzites. Having refitted and ob- 

 tained an escort, we left Fort Ellis on tbe 15tb, and, after a ride of but 

 nine miles over a very rougb road, went into camj). During tbe day 

 we passed over fossiliferous sandstones of Tertiary origin. At tbe bead 

 of Spring Caiion, tbrougb wbicb a small stream flows to join tbe Galla- 

 tin, we passed an old coal-mine. ■ It is abandoned, and being full of 

 water prevented our entrance. Tbe sbaft, bowever, does not penetrate 

 very far. Tbe coal is lignite, similar to tbat found along tbe Union 

 Pacific Eailroad. On top of tbe sandstones we again bad igneous rocks, 

 (dark basalts.) For tbe two following days we were obliged to travel 

 very slowly, baving to build our road in many places. Tbe sandstones 

 and basalts continued until we reacbed tbe valley of tbe Yellowstone 

 Eiver, wbicb we entered on tbe morning of tbe 17tb. Tbe flow of tbe 

 lava bas sjjread out over tbe valley, forming a floor, over wbicb our road 

 led. I obtained on our way cbips of cbalcedony and obsidian, wbicb 

 were abundantly scattered over tbe valley. 



Tbe valley of tbe Yellowstone, at tbe point we entered it, is about 

 four miles wide, and bas on its eastern margin a grand mountain range, 

 wbose sbarp peaks proclaim its volcanic origin. Tbe river is easily 

 traced by tbe line of timber on its banks. At Botteler's Eancb we 

 formed our permanent camj), being unable to take our wagons fartber, 

 and made preparations to pursue our way witb pack-mules. On tbe 

 20tb of July we left Botteler's, stringing out in single file, witb our 

 pack-train along tbe trail up tbe Yellowstone Eiver. Tbe trail led us 

 along tbe left bank of tbe river over igneous rock, tbe most conspicuous 

 of wbicb was a breccia composed of large masses of black material 

 imbedded in a red matrix. After a ride of about fifteen miles we reacbed 

 tbe lower caiion. Here tbe river breaks tbrougb masses of gneissic 

 rock, wbicb rise abruptly from tbe water's edge, and over wbicb our trail 

 was very steep and rocky. Tbe caiion is about tbree- quarters of a mile 

 in lengtb and about 280 feet wide. At tbe bottom of tbis ravine tbe 

 river j of an emerald tint, rusbes over tbe rocks, wbose resistance causes 

 it to be tbrown into numerous foam-capped ripples. Tbe gneissic rocks 

 are for tbe most part garnetiferous, tbougb somewbat indistinctly so. 

 Tbey pass in many places into bornbleude scbists, and in otbers become 

 granitoid. Emerging from tbe canon, our way led us alternately over 

 low bills of igneous origin and expanded valleys. Tbe soil seems to be 



