108 GEOLOGICAL SURVEY OF THE TERRITORIES. 



This calculation assumes that the sulphides are as follows, viz : Per cent. 



Galenito 38.69 



Stibiiite 3.30 



Biniiito 1.0:} 



SpLialerite, (bleude) 3.62 



P y r i t e - 5.42 



Argeutite - 0. 54 



52.60 



This statement excludes the presence of any other gangue than silica, and, consider- 

 ing that the ores exist in limestone, the almost total absence of lime in the composition 

 of the average mass is certainly remarkable. The amount of silica fonnd is noticeable, 

 since quartz is not seen as such in this great ore-chamber, nor, so far as I could Hud, in 

 other parts of the mine. The silica can have existed in chemical combination only in 

 the most inconsiderable quantity, since the bases Avith which it could have combined 

 are present to the extent of less than H per cent. ; nor do we iind in the mine any 

 noticeable quantity of kaolin or lithomarge resulting from the decomposition of sil- 

 icates, nor are there any feldspathic minerals. It is most probable that the silica existed 

 in a state of minute subdivision, diffused in the sulphides as I have seen it in some of 

 the unchanged silver-ores of Lion Hill, in the Oquirrh Range. 



The absence of chlorine and of phosphoric acid in the analysis corresponds vp'ellwith 

 the absence of the species cerargyrite and pyromorphite, of which no trace could be 

 found by the most careful search among the contents of the mine. 



From the Flagstaif and Silver Star lobtaiued specimens of wulfenite, 

 auricbalcite, galeuite, lithomarge, massicot, cervantite, aud cerussite. 

 The wulfeuite I found in minute, brilliant, yellow, tabular crystals, in 

 cavities in ocbraceous ores, and also associated with cerussite. Other 

 minerals found at this locality are azurite, malachite, calamine, angle- 

 site, sphalerite, jiyrite, argentite, antimonial, galenite, anglesite, kaolin, 

 and limonite. 



A specimen of galena from the Vallejo tunnel of the Silver Star mine 

 yielded, on examination, a small percentage of silver. 



Among the rocks I obtained while at Ogden were specimens of aplite, 

 protogine, hornblendic gneiss, protogenic gneiss, chlorite, schist, aud 

 micaceous schist. 



Before closing this chapter I wish to express my thanks to Messrs. 

 Nettleton and Somers, of Colorado Springs, aud the officers of the Colo- 

 rado Central Eailroad in Golden City, for favors aud iuformatiou 

 afforded us while in Colorado. 



CHAPTER 11. 

 FORT ELLIS TO GARDINER'S RIYER. 



On the 22d of June the expedition was divided into two parties at 

 Ogden, and I found myself a member of the party which was to make 

 Fort Ellis, Montana, the base of operations. Accordingly, after a long 

 and tedious stage-ride, we pitched our tents near Fort Ellis on the 29th of 

 June. Fort Ellis is situated at the head of the Gallatin Valley, on one of 

 the many small streams that contribute to form the East Gallatin Riv^er. 

 The Gallatin Valley is one of the most fertile iu Montana Territory, and 

 is surrounded by ranges of mountains which contain choicest bits of 

 scenery as well as contribute to the wealth of the Territory. The prin- 

 cipal towns of the Gallatin Valley are Bozeman, Hamilton, and Gal- 

 latin City. The former contains a population of about live hundred 

 inhabitants. Between Bozemau and Gallatin City there are numerous 

 well-cultivated aud productive farms. 



