302 Prof. Baron F. Richthofen — On the Origin of the Loess. 



liad the character of a steppe, and been subjected to a climate 

 similar to that which prevails at present in western Siberia. 



Thus, Dr. Nehring, who, at that time, had no knowledge of my 

 researches, was led through the study of the fossil remains to 

 precisely the same conclusion regarding a limited region in Europe, 

 at which I had arrived with respect to a large portion of the 

 continent by arguing on the structure and mode of occurrence of 

 the Loess. Since then, the continued studies of the bones of mam- 

 mals contained in the Loess, which have been made by Dr. Nehring 

 and others, have yielded an overwhelming amount of evidence 

 in the same direction, and have enabled us to extend the first 

 conclusions to the whole of Germany, including the Ehine valley, 

 Bohemia, and the vicinity of Vienna, and also to Hungary, 



I believe I am correct in stating that, among those who have 

 had extensive experience in Loess regions, all who have pronounced 

 an oj^inion of late 3'ears are agreed that subaerial deposition is 

 the only mode of origin by which all its peculiar features can 

 be easily explained. Besides Mr. Eaphael Purapelly, who knows 

 the Loess of Asia and North America, I mention chiefly Dr. Emil 

 Tietze, of Vienna,^ who studied it in Persia and Galicia, and the 

 late Professor Karl Peters, of Gratz, who has probably examined 

 a greater extent of European Loess regions than any other geologist, 

 and, like Pumpelly, had, previous to 1877, advocated an aqueous 

 origin as strongly as he afterwards did the subaerial. The cele- 

 brated M. von Middendorff has lately changed his views in a similar 

 way.^ 



According to the subaerial theory as here pointed out, two different 

 climatic stages are required for the formation of the typical Loess 

 regions, the first of them marked b}^ a continental and generally dry 

 climate, during which the soil accumulated, the other distinguished 

 by an increase in the fall of rain, in consequence of which the soil 

 was furrowed b^^ the erosive power of water and the steppe basins 

 were converted into Loess basins. It is obvious that the conditions 

 afforded for the existence of plants and animals and for the mode of 

 life of mankind must have been almost the reverse of each other in 

 either of the two stages, and that their change in time corresponded 

 exactly to their change in space, as witnessed at present by the 

 traveller when he descends from the Mongolian salt steppes with their 

 uniform vegetation, their animals peculiarly adapted to a roving kind 

 of life and their nomadic and lanagricultural people, to the Loess basins 

 of China, the characteristic feature of which consists in the labyrinthic 

 iramification of very narrow gulches cut in the yellow soil to very 



1 Jahrtucli der K. K. geolog. Eeichsanstalt in "Wien, 1877, pp. 341-371; and 

 more fully explained in the same journal for 1882, pp. 111-149. This last notice, 

 which is of great importance, came to my knowledge after writing the present 

 article. 



2 Mem. de I'Acad. Imp. des Sc. de St. Petershourg, t. xxix. 1881. It appears 

 that Mr. W. T. Blanford has also adopted the theory of the subaerial origin of the 

 deposits filling up undi'ained inland basins (see Proceed. E. Geogr. Soc. 1881, p. 79), 

 and Mr. Clarence King informs me by letter that he ardently advocates the same 

 mode of origin regarding the Loess regions of the Mississippi basin. 



