NBL. 
BPS tae) = hs 
eee Noon Vee neceh  a — Nias: 
of the Scratched Lock Surfaces. 13 
Overlying, this, but resting generally on the rock, is the 
marl 2 of No. I. division. To this succeeds the second di- 
vision: 1. The shell-clay, &c.; 2. The brick-clay; 3. Sand 
ATT £5 een [ 2. Brick-clay. (No. U. 
<> ey em cm, —_— me ee ie ee = 1, Shell -clay. 
| Mar! and sandy 
clay. 
stones in shel- 
tered corner. 
Granite. 
| 
or sandy clay, on which large boulders rest loosely. Through 
these a valley has been cut, where, however, the section 
presented in its banks is as often obscured by alluvium. 
A diminution of the glacial cold, and along with this a 
great thawing of the inland ice, seems to have occurred be- 
tween the deposition of the marl with its associated shell- 
beds and the later shell-clay, for the more markedly arctic 
character of the Fauna is wanting in the latter clay. Hence 
the division of the beds into the glacial and the post-glacial 
groups. 3 
This shell-clay was a regular marine formation, deposited 
in a perfectly orderly and quiet state of things; but after 
its formation there must have followed a time of floods, 
during which the many dams, forming basins and lakes in 
the valleys, were cut through, and the clay, the sand, the 
period which we possess. They were formed at the same time that the rock 
surfaces in the lower districts were striated under the general covering of 
ice. The greatest mass of the boulder-clay, however, formed during that 
period, seems to have been either thrust into the sea and left at depths still 
below our reach, or so mixed up with the boulder-clay of a later period as to be 
undistinguishable from it. That our existing boulder-clays generally belong 
to a later period is obvious, since they are contemporary with the marls, which 
are a sea deposit, formed on the submerged land, which had previously been 
furrowed and scratched by the old ice-covering grinding over its surface, and 
leaving its detritus only in such places as were protected from the motion of 
the ice.—[ Translator.] 
. Boulder-clay & pNo. L 
