522 
CHARACTER OF DRIFT IN GERMANY AND POLAND. 
The nature of the superficial detritus which occupies the surface of that area is 
much in favour of this view. For a considerable space to the west of the Ural, 
there is not a vestige of any superficial deposit which can be referred to the in- 
fluence of the sea ; no far-transported blocks — no finely levigated sands and dunes 
— no great diluvial hillocks of clay and drift ; but, on the contrary, all the detritus, 
like that of the Ural and Siberia, is local and small. We believe, therefore, that 
the region so characterized was really above the waters and inhabited by mam- 
moths, when the erratic blocks were transported over the adjacent north-western 
sea, and that the then coast of the Siberian and Uralian lands advanced near to the 
line marked on the Map as the extreme boundary of the granitic erratics, which 
were, we believe, stranded on or near the shelving shore of these ancient lands. 
In speaking of Russia, we have already endeavoured to show, that the drift has 
been diversified and added to, as it passed southwards, by deriving new materials 
from each zone of rocks which it traversed. The Silurian and Devonian deposits, 
which contain few hard beds, have not, as might be expected, furnished many 
boulders, their debris consisting chiefly of grey and red mud and sand ; but the 
carboniferous limestone, containing bands of flint and chert, fragments of these 
have been most largely distributed, and being readily known by their included 
organic remains, are valuable “ drift marks,” if we may use the expression. In 
proof of the uniform direction of the drift, we may state, that there is no instance 
of one of these flints having been found to the north of the carboniferous zone, 
from -whence alone they can have been derived, whilst they are profusely scattered 
over its surface and extend for vast distances beyond its southern limits. This 
phenomenon is in perfect accordance with what we have observed in the country 
of Siluria and other tracts of Western Europe, where the direction of drift in any 
particular line may be tested by the addition of fresh materials of the subsoil over 
which it passed. 
In treating, however, of the great block region of all the northern states, it must 
be said, that these indicia of the character of the subsoil in each of the successive 
geological tracts, proceeding from north to south, are confined to Russia ; for 
in Northern Prussia and Poland no rocks whatever have been detected even in 
the deepest denudations. The northern materials, with the occasional detritus 
of Swedish Silurian strata, are there alone mixed up with sands and clay of 
uniform colour, chiefly the spoil of the tertiary deposits ol those countries. In 
Mecklenburg and Prussia the blocks occur, for the most part, as in Russia, on 
