922 PROFESSOR J. PRESTWICK ON THE EVIDENCES OP A SUBMERGENCE 
and when the storm bursts, the valleys viewed from a height, disappear in the dust 
which forms into waves that the tempest hurls in all directions, building up mountains 
of sand. These vast sandy tracts are dotted with tamarisk trees, which serve to stay 
the moving, surface of the desert. M. Bonvalot attributes these dust-storms which 
were experienced up to heights of 14,000 feet or more, moving enormous waves of the 
sand eastward, to the erosive power of the winds on low chains of crumbling marls. 
The great height of the land, the vast thickness and the irregularity of the deposit, 
and the absence of river- or sea-shells, preclude, as Bichthofea’ justly observes, our 
looking upon this deposit as due either to marine or fluviatile sedimentation, whilst 
the irregularity in its dimensions, the variable and great heights at which it occurs, 
and the character and position of its entombed organisms, are all such as might ensue 
from the action of devastating winds and overwhelming dust clouds. If we could 
suppose snowdrifts to be consolidated and remain in permanence, the annual incre¬ 
ments would in a period comparatively short, fill up valleys and accumulate in vast 
masses in the more sheltered places, and it is in manner like this that I presume we 
are to understand that the so-called Loess of China has been formed. 
But there are many conditions at variance with those of the European Loess. 
Amongst them, it may be observed, that the latter is generally but from 10 to 50 feet 
thick, and only occasionally attains a thickness exceeding 100 feet or attains the 
wind-devastating heights of the other. The European Loess also exhibits not infre¬ 
quent traces of water action, and the organic remains are not in their original position 
and entirety, but are scattered and dispersed. The bones of the animals especially are 
almost always found single, often in isolated fragments, and are very few in number, 
whereas if buried by the dust, as we presume they were in China, on or near the spot 
where they died, the whole skeleton, more or less entire, should be found in situ. 
Further, the climatal conditions under which the two deposits were formed, seem to 
have been entirely distinct. 
While, therefore, I would accept Baron von Bichthofen’s explanation for the 
remarkable wind-formed deposit of China and Central Asia, it does not seem applicable 
to the Loess of Europe.* 
Dr. A. NEHRiNot describes a Loess in Northern Germany which claims to have some 
points of analogy with that of Bichthofen, but the evidence seems only of local 
application, and not to be generally conclusive. The Mammalia he names are mostly 
the ordinary species of the Quaternary fauna in Western Europe.—J.P., April, 1893.] 
The plateau Loess in Francej and Belgium is often divisible into two parts. In some 
cases this feature (which may be also occasionally seen in England) is due to secondaiy 
* Otlier objections are stated by Professor James Geikie in “ Prehistoi'ic Europe,” 2nd edit., 
pp. 165, 244. 
t ‘ Geol. Mag.’ for 1882, p. 570, and various previous papers in German periodicals. 
t Amongst tbe many otbei' papers on this subject those of MM. H^bekt and De Meecet for the north 
of France should be consulted. 
