6Q GEOLOGICAL SURVEY OF THE TERRITORIES. 



deposits are found higii up on the mountain-sides, showing that at a 

 very modern date the valleys of most of the streams must have been 

 connected through the low passes, yet the princii)al sedimeuts are in 

 the lower basius. Indeed, I could imagine that the entire Northwest 

 (and how much more of the country I cannot now positively deter- 

 mine) presented much the appearance of the basin of Great Salt Lake, 

 with the numerous mountain-ranges rising above the waters. Now, if 

 we can imagine the entire area of the great basin between the Wah- 

 satch Mountains and the Sierra Nevada covered with water to a height 

 which it must have reached at a comparatively modern geological 

 period, the vast number of mountain-ranges of greater or less size 

 which now exist within these limits would represent so many rock}^ 

 islands in this vast inland sea. Here and there in the valleys of the 

 ]Madison, as well as the Gallatin, the older rocks are exposed beneath 

 the lake-deposits, even where the latter prevail. We can trace out with 

 more (h'taii the skeleton of the surface prior to the laying down of the 

 lake-deposits. In the lower valleys it is quite rare to lind rocks more 

 modern thau the Carboniferous, but the limestones and granites crop 

 out oftentimes in the most unexpected places. The stripping away of 

 the lake-de[)osits froui the metamorphic rocks in the range through 

 which the Lower Canon is formed has exposed a moderately rich min- 

 ing district. There are a number of mines which are wrought with 

 success at this time, and ou the whole the mining prospects of all this 

 region are becoming better every year. The excellent reports of Mr. 

 K W. Raymond, Commissioner of Mining Statistics, are so full iu 

 regard to the mines of Montana that I shall at present touch this sub- 

 ject very briefly. 



It is my intention to study all the mining districts of Montana at 

 some future period with special reference to their geological rela- 

 tions, carefully mapping the lodes, and endeavoring to study out if 

 possible their natural history. I believe, that Montana is rich in 

 valuable mines, and that, when railroad communication has been estab- 

 lished between it and the world at large, an impulse will be given to the 

 mining interests of the Territory that will .satisfy the most sanguine. 

 It behooves the enterprising citizens not to let the subject of railroad- 

 communication rest from this time until it becomes an accomplished fact. 

 The world will then begin to appreciate the resources of the Territory, 

 which, so far as I have examined it, surpassesany of the others in the West. 

 The Cherry Creek Mines occur in what has been called the Madisou 

 range. The reader is referred to the report of Dr. Peale for such informa- 

 tion as he has been able to secure in a brief visit to them. This mining- 

 belt passes across the Madisou "by way of the Lower Cahon, and extends 

 to the South Bow Ider Mountains. Hundreds of lodes have been opened, 

 Diany of them worthless ; but mauy others would doubtless prove valu- 

 able if transportation and labor were not so costly and difficult to obtain in 

 the country. The lodes are all found in the metamorphic strata, the age 

 of which it would be difdcult to decide. We only know that they form 

 a vast thickness of stratified rocks with varied texture and composition. 

 They seem here to have been subjected to considerable erosion after the 

 limestones were washed away. These metamorphic strata underlie the 

 entire country and appear everywhere where the unchanged beds have 

 been worn away or when not concealed by the outflow of igneous 

 matter. The work of reducing these metamorphic' strata to a system, 

 and conntH^tiug them over extended areas, has not yet been attempted, 

 and it seems to me an almost hopeless as well as fruitless task. It will 

 be enough for the i)resent generation, pin-haps, if we are enabled to work 



