472 Reports and Proceedings—British Association— 
while all the positive evidence we have points rather to humidity 
than dryness as the prevalent feature of Pleistocene climates. It is 
obvious, however, that after the flood-waters had disappeared from 
the low grounds of the Continent, subaerial action would come into 
play over the wide regions covered by Glacial and fluvio-Glacial 
deposits. Thus, in the course of time, these deposits would become 
modified,—just as similar accumulations in these islands have been 
top-dressed, as it were, and to some extent even rearranged. I am 
strengthened in these views by the conclusions arrived at by M. 
Falsan, the eminent French glacialist. Covering the plateaux of 
the Doubs, and widely spread throughout the valleys of the Rhone, 
the Ain, the Isére, etc., in France, there is a deposit of léss, he says, 
which has been derived from the washing of the ancient moraines. 
At the foot of the Alps, where black schists are largely developed, 
the loss is dark grey; but west of the secondary chain the same 
deposit is yellowish, and composed almost entirely of siliceous 
materials, with only a very little carbonate of lime. This /imon or 
loss, however, is very generally modified towards the top by the 
chemical action of rain, the yellow léss acquiring a red colour. 
Sometimes it is crowded with calcareous concretions; at other times 
it has been deprived of its calcareous element and converted into a 
kind of pulverulent silica or quartz. This, the true léss, is distin- 
guished from another lehm, which Falsan recognizes as the product of 
atmospheric action—formed, in fact, in place from the disintegration 
and decomposition of the subjacent rocks. Even this lehm has 
been modified by running water—dispersed or accumulated locally, 
as the case may be.! 
All that we know of the loss and its fossils compels us to include 
this accumulation as a product of the Pleistocene period. It is not 
of post-Glacial age—even much of what one may call the ‘“‘ remodified 
loss” being of Late Glacial or Pleistocene age. I cannot attempt 
to give here a summary of what has been learned within recent 
years as to the fauna of the loss. The researches of Nehring and 
Liebe have familiarized us with the fact that at some particular 
stage in the Pleistocene period a fauna like that of the alpine 
steppe-lands of Western Asia was indigenous to Middle Europe, and 
the recent investigations of Woldrich have increased our knowledge 
of this fauna. At what horizon, then, does this steppe-fauna make 
its appearance ? At Thiede Dr. Nehring discovered in so-called léss 
three successive horizons, each characterized by a special fauna. 
‘The lowest of these faunas was decidedly Arctic in type; above that 
came a steppe-fauna, which last was succeeded by a fauna comprising 
such forms as Mammoth, woolly Rhinoceros, Bos, Cervus, Horse, 
Hyena, and Lion. Now, if we compare this last fauna with the 
forms which have been obtained from true post-Glacial deposits— 
those deposits, namely, which overlie the younger Boulder-clays and 
flood-accumulations of the latest Glacial epoch, we find little in 
common. The Lion, the Mammoth, and the Rhinoceros are con- 
spicuous by their absence from the post-Glacial beds of Hurope. 
1 Falsan : La Période glaciaire, p. 81. 
