Climate^ Geography and Geology of Minnesota — Upham. 151 



thermal springs of the interior basins, show that the underground 

 forces of the globe, so largely instrumental in elevating and shap- 

 ing the continents, are by no means wanting here. If it is the 

 case that the western side of the continent is continual^^ rising 

 then the climate of the plains to the east will continue to grow 

 drier until it becomes too arid to support any form of vegetable 

 life. Our records do not cover sufficient time to say if the mean an- 

 nual rainfall is diminished. It is a noticeable fact, however, that 

 there is a gradual drying up of many marshes and small streams 

 throughout Minnesota and North Dakota. It is usually supposed 

 to be due to the breaking up of the sod, causing the rain and 

 melting snows to sink into the ground instead of collecting in 

 ponds. But it is plainly to be seen that there has been a gradual 

 loss of water long before any ground was broken. The river 

 channels are more contracted, the lakes show that they formerly 

 stood at a much higher level, and narrow arms or inlets of lakes, 

 together with numerous small ponds, have become shallow marshes 

 and peat bogs. These results should in the main, I think, be 

 ascribed to a continuous slow elevation of the country, causing 

 more or less disarrangement of the subterranean water courses, as 

 shown in the drying up of springs, in furnishing a more rapid 

 drainage and in decreasing the mean annual rainfall and tem- 

 perature. 



May 4, 1886. 



[Paper V.'\ 



DKSt'KlPTION OF MA.PS SHOWING THE CLIMATE, GEOGRAPHY AND 



GEOLOGY OF MINNESOTA.— 5// Warren Upham. 



The exhibit in the New Orleans exposition, 1884-85, by the 

 geological and natural history survey of Minnesota, included 

 twenty maps showing the climate, geography and geology of the 

 state, prepared by the writer under the direction ^of Prof. N. H. 

 Winchell, the state geologist. 



Four of these maps show the climatology. 



1. Mean annual rainfall: 34 inches in the southeast corner 

 of the state; 28 to 32 about lake Superior and Rainy lake; thence 

 diminishing westward to 22 at Moorhead and Fargo and at lakes 

 Traverse and Big Stone on the west boundary of the state. It is 



