1877. ] The Chinese Loess Puzzle. TOT 
coast-line formerly extending farther out into the sea than it now 
does. So much for the horizontal and vertical distribution of the 
loess, and now some of its structural conditions may be noticed. 
Two peculiarities strike the eye of the observer at once on ex- 
amining the material in question : in the first place, the entire 
absence of any indications of stratification ; and, second, the tend- 
ency which it everywhere exhibits to cleave or crack in vertical 
planes. These peculiarities, however, would not make such a 
strong impression on the mind of the geologist if it were not for 
the enormous thickness of the deposit, which is usually several 
hundred and in places reaches fifteen hundred or even two thou- 
sand feet. To see such a mass of material, not of igneous origin, 
destitute of any indication of stratification, is something entirely 
out of the ordinary experience of the geological observer. It 
would seem impossible that such a deposit could have been laid ` 
down except from water , and, if so, where are the lines of depo- 
sition, which never fail to make themselves visible in aqueous 
sediments? The problem, as will be seen, begins to present it- 
self as a puzzle. But it may be asked, Is not this a deposit from 
water, in which, owing to some peculiar conditions, the lines of 
stratification have become obliterated? The answer to this is 
readily given in the negative, when on investigation it is found 
that this deposit, hundreds of feet in thickness, contains imbedded 
within its mass no fossil remains of marine or fresh-water origin, 
but only land shells — mostly those of snails —and occasional 
bones of land animals. It is evident, then, that this so-called loess 
is not similar in origin to that of the Rhine Valley, as indeed 
might easily have been inferred from its position at all elevations 
over plain and mountain side ; but that it is a subaerial deposit. 
Apart from theoretical considerations of origin, which make this 
loess formation so interesting, there are other circumstances re- 
sulting from its mode of occurrence, which bear on the daily life 
of the people inhabiting these loess-covered districts, and so con- 
nect themselves with their agriculture, their roads, and their 
means of military defense as to be abundantly striking, even to 
~ the observer who cares nothing for geological problems, and to 
whom the absence of lines of stratification would not appear as a 
noticeable fact. The peculiar type of scenery which these great 
_ areas, covered by such a thickness of soft, easily eroded material, 
_ present could not fail to impress itself on the mind of the most 
careless observer. And we find that the main features of the 
landscape in the loess districts are closely connected in their ori- 
