244 PREHISTORIC EUROPE. 



of the great rivers that flow into the Black Sea and the Caspian, 

 and even floated for some 300 miles farther south, why should 

 their journey have been so suddenly arrested? Why should 

 not they be scattered over the whole breadth of the Steppes, 

 or disclosed to view in the beds of the numerous rivers by 

 which those wide regions are intersected ? 



In the foregoing remarks upon the origin of the loss and 

 other loamy deposits pertaining to the same or approximately 

 the same period, I have dwelt upon various phenomena which 

 seem to me to bear strongly against the wind-theory advanced 

 by Eichthofen. There are many other objections which might 

 be urged to that view, but I shall specify only one or two. 



1. The physical conditions of our continent during Pleis- 

 tocene times would not permit of the existence of a desiccated 

 central area, like those arid deserts of Asia referred to by 

 Eichthofen. The loss unquestionably forms part and parcel of 

 the glacial accumulations, and the climate at the time of its 

 deposition, as its shells alone prove, must have been not only 

 colder, but more humid than the present. Even if Europe 

 generally had stood at a higher elevation then than now, still 

 that could not have converted any part of our area into a dry 

 desert. In point of fact, as we shall see in the sequel, genial 

 and humid conditions prevailed generally throughout Europe 

 at a period when the land stretched considerably farther into 

 the Atlantic, the British Islands then forming part of the 

 Continent, and the area of the Mediterranean Sea being con- 

 siderably reduced. The dry sandy tracts of Central Asia and 

 of the great basins and plains in the Western Territories of the 

 United States have no analogues in Europe. We have nothing 

 here comparable with the phenomena of wind-erosion described 

 by Mr. Clarence King and others as characteristic of the sandy 

 plains of Western America, where the wind has undercut and 

 gradually demolished masses of rocky strata by the filing action 

 of the sand driven before it. Mr. King informed Mr. Pumpelly 

 that the prevailing westerly wind, carrying sand, has carved and 

 polished the rocky crest of the Sierra Nevada, and formed long 



