GEOLOGICAL SURVEY OF THE TERRITORIES. 279 



appreciates the value of the surface-geology of this section, in which 

 he speut so mauy of the early days of his exploiations, than he does. 

 Professor Winchell, in his first annual report of the Geological and 

 Natural History Survey of Minnesota, has devoted a short chapter to 

 this subject so far as it relates to that State. Owen, in his Kei)ort on 

 the Geology of Wisconsin, Minnesota, and Iowa, mentions numerous 

 important facts bearing upon this subject, but does not discuss it 

 specially. But no one, so far as 1 am aware, has as yet discussed the 

 relation of the last geological change in this section to its presenb 

 climatic condition. This, therefore, still remains an open field for 

 inquiry and investigation. 



The valleys of the rivers, the weathering of the bluffs and terraces, 

 the dry coulees, as well as the vast amount of local drift near the base 

 of the Rocky Mountains, show beyond a doubt that, at some very recent 

 period in a geological sense, the amount of water which fell was much 

 greater than at present. I allude not to the remote period, when it was 

 submerged, but to a period since the waters receded, for it requires no 

 geological eye to detect these evidences and to determine that they 

 relate to a time long subsequent to the last emergence, hence attribut- 

 able to rain and snow. 



It is therefore evident that between that time and the present a great 

 change has taken place in the climate in regard to humidity; that it is 

 much less now in the western portions of Dakota, Nebraska, and Kansas 

 than it was in the past. This question then arises: Has the change in 

 this direction ceased ? If not, then we are forced to the conclusion 

 that this section is still growing drier. If it is true — and I think it will 

 scarcely be denied by any who have directed their attention to the sub- 

 ject — that such has been tlie direction of the climatic changes in the 

 past, one of two conclusions is inevitable, viz, that there are n*) grounds 

 for expecting a more favorable climate (in regard to humidity) in the 

 future, ©r that the change in the direction indicated has ceased, and 

 consequently a reaction must take i)lace. On this important point I 

 have collected some data which I expect to present in my meteorological 

 report. 



As the immense belt under consideration is one almost continuous 

 prairie, devoid of forests, which must be devoted almost wholly to farm- 

 ing and pastoral pursuits, it is apparent that its future development 

 depends to a great degree upon the means of transporting its products 

 to market and of reaching the forests of the States lying east of it. It 

 is therefore very desirable, in this connection, to obtain some idea of the 

 extent and character of the forests and the extent and direction of the 

 coiistructed and contemi)lated railroad-lines. 



Although I have not made the former a special object of inquiry and 

 investigation, yet sufficient information in regard thereto has been 

 obtained upon which to found a conclusion in regard to the adequacy of 

 the supply of lumber for the next generation. To examine the immense 

 forests of Minnesota and Wisconsin in person, with sufficient thorough- 

 ness to determine their character, would require several years; but, 

 fortunately, these States have for several years been gathering statistics 

 concerning them, which are accessible, and of which I shall avail myself 

 in this or a future report so far as I deem it necessary to do so. 



Any report relating to the present extent of the railroads would be of 

 but temporary value, as the various lines are beiiig so rapidly extended, 

 and new ones being formed in such rapid succession, that what is true 

 to-day will fall far short of being true a few years hence. 



A very important question, and one of national interest, arises in con- 



