1871.] ETjS^GSMILL CHINESE " LOESS." 381 



sphere. The layer formed by one generation of plants would, in 

 effect, have been absorbed by the next without any addition being 

 possible. 



Dust-storms, however, have been suggested as a source of supply. 

 Unless these passed over deposits of the Loess itself, I know of no 

 other source for the necessary ingredients. Clay would not be 

 acted on by the wind ; sand, of itself, would not suffice to form the 

 peculiar mixture of ingredients ; limestone rocks have never, to my 

 knowledge, beeii so disintegrated by the action of the atmosphere 

 as to become reduced to dust capable of being transported in the 

 manner suggested. The means are therefore utterly inadequate to 

 the end. 



Easy removal of the Loess by rain. — There are, however, other 

 grounds of objection. Had the Loess been formed as dry land, there 

 is no reason why it should not only have utterly ceased to increase, 

 but should be actually undergoing a rapid destruction. There is evi- 

 dence sufficient to prove that its waste now is greater than at former 

 periods, owing to the ignorant destruction of the trees with which, 

 tradition states, it was once covered. This destruction has increased 

 the frequency and force of the annual floods ; but as long as rain 

 fell or rivers ran, denudation of one sort or other must have been 

 going on. Denudation above the sea-level is, in fact, as necessary 

 an accompaniment of running water as is deposition below it. When 

 it is remembered how sensitive is the Loess to the slightest contact 

 with water, and that ever since the emergence of the Loess district 

 from the waves every stream within its limits must have been con- 

 tinually engaged in the work of denudation, the difficulty of accept- 

 ing the subaerial theory becomes a practical impossibility. 



Marine origin of the Loess. — Rejecting, then, as untenable the 

 theories which would assign a glacial, freshwater, or subaerial origin 

 to this peculiar formation, little remains except to class it as marine. 

 As yet, except in its peculiar structure, such as its mechanical re- 

 semblances to chalk, an undoubted deep-sea formation, no internal 

 evidence has been discovered to guide us to this conclusion. Speci- 

 mens of the clay were sent by Mr. Pumpelli to the United States, 

 and examined microscopically by Mr. Edwards ; except, however, 

 some small green crystals, pronounced not to be organic, nothing 

 peculiar presented itself. There are here no means of making mi- 

 croscopic examinations, and but few for scientific operations of any 

 kind ; inductions have therefore to be founded on what, under more 

 favourable circumstances, would be deemed insufficient proof, trust- 

 ing to stibsequent rigid investigation to prove or disprove their truth. 

 The real origin of the Loess wOl probably be proved by the close 

 examination of its microscopic structure ; but even this must be to 

 a certain extent taken in connexion with its external conditions, as 

 Microzoa may readily be of derivative origin. 



Probahle Geological relationships of the Loess. — The assumption of 

 a marine origin for the Loess of eastern Asia leads up to most im- 

 portant geological deductions. It extends, as has been stated above, 

 from the south of the Yangtsze, in the prefecture of Chinkiang, far into 



