1871.] KINGSMILL CHINESE " LOESS." 379 



the Yangtsze ; the elevated sandstone plain of northern Anhwei is in 

 places defined by escarpments of the older mountain-chains, rising 

 abruptly from its surface. The traveller in this district is, in fact, 

 forced to the conclusion that he is passing over an ancient sea- 

 bottom, the mountain-masses of the older Devonian and Carboni- 

 ferous formations forming islands, rising in lines of irregular cliffs, 

 which from their indented outline betoken a long-continued period of 

 depression. 



These rocks are succeeded by the Loess. Before its deposition 

 they seem to have been partially, though slightly, denuded, denoting 

 probably some change in the physical conditions of the adjoining- 

 land. 



What is true of the four provinces adjacent to the Yangtsze is 

 probably true, likewise, with regard to the others over which the 

 Loess extends. There was, at some time subsequent to the upheaval 

 and denudation of the Carboniferous and apparently Triassic rocks, 

 a period of considerable depression in, at least, Central China. The 

 deposition of the Loess probably marked its close. 



I have assumed the age of the sandstones and gravels to be Ter- 

 tiary, principally from their position, overlying all the older rocks, 

 and because comparatively little denudation has occurred in either 

 them or the older rocks since their deposition. As stated above, the 

 evidence of fossils is as yet wanting; but we may hope to see it sup- 

 plied. The main fact of the depression antecedent to the deposition 

 of the Loess may be regarded, however, as proved. 



Structure of the Loess. — The other argument adduced in support 

 of the subaerial theory, as stated above, is founded on the internal 

 evidence of the deposit. Baron von Richthofen holds that the Loess 

 is unstratified ; this, so far as relates to the absence of apparent 

 layers of deposition, is true, as it is likewise of the Loess of the Ehine. 

 As in the latter, however, the beds of calcareous nodules point to an 

 apparent stratification of materials. In this respect, as in others to be 

 pointed out, it bears a close mechanical resemblance to chalk, though 

 in mineral composition very difi"erent from that rock. The occurrence 

 of land-shells and remains of land-animals is looked upon as a strong 

 proof in support of this theory. The fossil origin of these exuviae, 

 however, is more than doubtful. The Loess is perfectly pervious 

 to water ; to use the Baron's own words, " It is perforated through- 

 out its mass by thin tubes, which ramify like the roots of grass, and 

 have evidently their origin in the former existence of roots." As a 

 fact, streams seldom or never flow on the surface of the Loess ; they 

 take by preference underground courses, or work for themselves 

 deep valleys, penetrating into the mass in all directions, like branches 

 from the stem of a tree. This mass has, besides, a tendency to 

 cleave in vertical planes, enabling thereby the smallest streams to 

 penetrate its mass ; so readily, moreover, is it acted on by water, or 

 even by aqueous vapour, that I have in my possession specimens 

 which disintegrated in the moist air of a Shanghai summer, and 

 which have since rearranged themselves at the bottom of the drawer 

 in which they had been placed. These facts render the presence of 



