74 * The Loess of the Rhine and the Danube. [January, 
of Belgium, enveloping Hainault, Brabant, and Limburg like 
a mantle. It extends into France, and covers the high 
plains between the rivers, and is most likely the same as the 
upland loams of the valleys of the Seine and the Somme, 
which occupy positions often independent of the present 
lines of drainage. It is even probable that it once covered 
the south-east of England, but has since been denuded, as 
Prof. Morris has shown to me some of its characteristic 
shells which he had gathered in patches of loess, preserved 
in fissures of the chalk, near Maidstone. 
There is also much evidence tending to prove that the loess 
is the equivalent in the river valleys of the northern drift that 
covers so much of Northern and Central Europe. Thus in 
ascending, from Vienna, the valley of the March, I found all 
the flanks of the hills covered with a loess like clay, which 
as I travelled northward changed to a redder colour. This 
clay covered the low watershed between the Danube and 
the Oder, to a depth of 20 feet in some places. The water- 
shed is only about 1000 feet above the sea, and the clay 
covers it and follows along the flanks of the hills on either 
side. On the northern flanks of the range, Scandinavian 
blocks, that must have been carried from the far north, are 
found up to heights of over 1200 feet. These occur all 
along the northern side of the Carpathians. The diluvial 
clay extends much higher. According to Prof. Stur it fills 
the valleys on the north slope, and I have always found it 
extending to much higher levels than the northern blocks. 
This is what we might expert, for the icebergs that brought 
the blocks from the far north must have required a consider- 
able depth of water to float them. 
In 1875, at Wolochisk, in the province of Volhynia, near 
the Russian frontier, whilst detained for the examination of 
luggage and passports, I found, in the clay that had been 
thrown out of a well, shells of Succinea oblonga and Pupa 
nmscorum, two mollusks that have left their shells in the 
loess almost everywhere where it occurs. This was not in a 
valley, but on the top of the flat plateau that forms the 
steppes of Southern Russia. I was much impressed with 
the occurrence of these characteristic loess shells at this 
place, as no higher ground overlooks the plain, and the clay 
may be followed continuously for hundreds of miles, and to 
the north contains transported Scandinavian rocks. On my 
return from a visit to Southern Russia, during the present 
year, I determined to examine this clay, which is “ the 
diluvium” of the Russian geologists, nearer to the mountains, 
and for that purpose stayed twelve hours at Podwolochisk, 
