Prof. Baron F. HicMliofen — On the Origin of the Loess. 303 



great depth and with perfectly vertical faces. It is this character of 

 surface, together with the fact of the existence of a drainage at low 

 level and the removal, by it, of the soluble salts, which causes the 

 remarkable contrast between the features of Northern China and those 

 of Mongolia. Vegetation offers there a far greater variety of forms ; 

 those animals which are accustomed to roving on the boundless steppe 

 cannot exist where the greatest possible unevenness of the soil is 

 the distinctive mark ; and man is simply forced to adopt in the 

 Chinese Loess regions a settled and agricultural mode of life, drained 

 Loess being of all kinds of soil best adapted for the cultivation of 

 cereals, while the innumerable recesses and naturally fortified posi- 

 tions afford him shelter and safety. 



It seems hardly necessary to observe, how important, on account of 

 this mode of origin, the occurrence of Loess is to the study of the 

 causes of the present distribution of plants and animals. The peculiar 

 climatic conditions prevailing during the time of its accumulation, 

 and the physical features of the regions covered by it must have 

 influenced migration and variation in a considerable measure, and it 

 is far from improbable that the habits of life and the migrations of 

 primitive man over large portions of Europe and Asia have been 

 directed by the same causes. It must be added that a slight 

 deterioration of the climate is sufficient to change the steppe, and 

 chiefly the drainless salt steppe, into the most arid desert, and to 

 cause the emigration of man and animals. 



I have given this expose a greater length than I intended. It 

 will refute, without any further discussion, the objections which 

 Mr. Howorth has raised against the theory of the subaerial origin 

 of the Loess, as, e.g. : that subaerial deposits such as this are nowhere 

 being formed now (p. 16) ; — that it is incredible that subaerial 

 deposits should have been deposited at a height of 6000 feet and 

 to the depth of 1000 feet (p. 76) ; — that the subaerial theory treats 

 the problem as a local Chinese problem, while it ignores that the 

 Loess has to be accounted for in Europe as well as in China 

 (p. 76) ; — that it cannot be understood how shells and animal 

 debris could be carried by the wind (p. 76); — that the means 

 would be inadequate to the end, as clay would not be acted upon 

 by the wind (p. 77, after Kingsmill) ; — that the chemical com- 

 position of the Loess does not correspond with that of the inorganic 

 elements of plants growing on its surface ; — that there is no known 

 means by which these inorganic matters could have been supplied 

 from the atmosphere ; — that, although silica might have been con- 

 veyed by the medium of dust storms, no way can be seen how the 

 silicate of alumina could be conveyed ; — that there is no evidence 

 of the ramifying tubes having their origin in the roots of plants ; — 

 that the Loess is devoid of organic substances ; — that Loess, if 

 subaerially deposited, should be different in composition accordingl 

 to the subjacent rock and could not be equal everywhere. I 



After having attempted to set aside, on these grounds, the theory 

 of the subaerial origin of the Loess, which, evidently, was known 



