DRIFT AND ERRATICS OF DENMARK. 
541 
In Denmark, indeed, whether in Holstein, Seeland or Jutland, the fundamental 
rock of the country, or chalk, is so covered with foreign materials, that in his 
valuable geological map of that region, our friend Professor Forchhammer has 
chiefly had to indicate their varied nature. In his description of these detrital 
masses he has shown, that though formed at different periods they are all charged 
with northern boulders. The earliest of these are beds, which he considers as 
closing the cretaceous epoch ; the included northern fragments (not, however, of 
great size) being in this instance associated with corallines. The next, in which 
boulders of considerable size occur, contains shells of the sub-apennine or miocene 
age — shells which bespeak a Mediterranean climate. The strata of these periods 
are here and there much dislocated, a phsenomenon which will not appear strange 
to those who have observed the highly inclined beds, also of miocene age, and charged 
with large boulders, which constitute the high peaks of the Snperga near Turin. 
No one has ever contended that such boulder beds of the north of Italy, associated 
as they are with shells of a former Mediterranean sea, were connected with glacial 
operations ; and as little can it be argued, that their analogues in the north should 
have been so formed ; any sort of glacial action under conditions of so warm a 
temperature being quite inadmissible. The succeeding superficial deposit in Den- 
mark, where it forms whole cliffs, is that which is, properly speaking, our Russian 
and German drift, or “ the boulder clay” of Forchhammer. In this western region, 
which is not far from the source of their origin, the blocks are often of gigantic 
size, and are associated with sands and sandy clay, containing fragments of modern 
shells, like those of the adjacent open northern sea, viz. Balanus, Corbula nucleus 
and Cyprina Islandica. According to Professor Forchhammer, this coarse drift has 
recently so undergone regeneration, as to form long ridges of sand and gravel which 
have been thrown up in reefs or shingle banks within the historic £era. 
Besides these boulders and their associates, there are other superficial deposits 
in Denmark which indicate successive elevations and changes. The blocks, for 
example, often occur in lines along great fractures or parallel to them, and are 
then associated with Mytilus edulis, Cardium edule, Buccinum reticulatum, all indi- 
cating raised beaches. Again, wherever blue clay prevails, the Mya or Hiatella 
Arctica occurs, which being a deep sea shell, indicates that it has been thrown up 
and mixed with littoral shells. It is unnecessary that we should here attempt to 
describe all the successive changes which have occurred in Denmark between the 
time of the transport of the coarse boulders and the present day. All wdrich it con- 
4 A 
