108 GEOLOGICAL SURVEY OF THE TEREITOEIES. 



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



Galenite 38.69 



Stibnite 3.30 



Bornite - 1.03 



Sphalerite, (blende) 3.62 



Pyiite -^ 5.42 



Argentite 1 ". 0.54 



52.60 



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

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

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

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

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

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

 are present to the extent of less than 1^ per cent. ; nor do we find in the mine any 

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

 icates, nor are there any feldsj^athic 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 Oquirrb Range. 



The absence of chlorine and of phosphoric acid in the analysis corresponds well with 

 the absence of the species cerai-gyrite and pyromorphite, of which no trace could be 

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



From the Flagstaff aud Silver Star I obtained specimens of wulfenite, 

 auricbalcite, galenite, lithomarge, massicot, cervantite, and cerussite. 

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

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

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

 site, sphalerite, pyrite, argentite, antimonial, galenite, angiesite, kaolin, 

 and limonite. 



A specimen of galena from the Yallejo 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, i^rotogenic gneiss, chlorite, schist, and 

 micaceous schist. 



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

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

 rado Central Eailroad in Golden City, for favors and information 

 aflbrded us while in Colorado. 



CHAPTER 11. 

 FOET ELLIS TO GAEDINEE'S EIVEE. 



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 Eiver. 

 The Gallatin Yalley is one of the most fertile in 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 five hundred 

 inhabitants. Between Bozeman and Gallatin City there are numerous 

 Veli-cultivated aud productive farms. 



