466 On the Post-Tertiary Beds [ Oct., 
In Scotland, careful study of the clay-pits will, we think, mani- 
fest a corresponding fact. On the lower part of the Dalmuir deposit, 
é. g., 18 a sandy clay, in which the arctic mollusca are very large 
and abundant ; but in the upper part of the bank, they are neither 
so large nor plentiful. The general aspect of a collection made 
from the upper and compared with one from the lower part, of 
almost any clay bed in the nighbourhood of Paisley, will indicate a 
striking difference of condition. : 
At the base, resting either on the boulder clay or the native 
rock, is the laminated mud, with a few foraminifera, evidently indi- 
cating conditions unfavourable to molluscan life. This is followed 
by a large and fine development of arctic shells, which often are so 
plentiful as to interfere with the economic working of the clay. 
These shells, however, gradually become more and more rare. 
Evidently they have been driven away by the shallowing of the 
water and other physical alterations. At last, in the uppermost 
marine clay, scarcely a shell occurs, until in the sands and gravels 
of the old river bed we have the remains of a fresh-water fauna. 
These deposits thus unfold a series of changes from the com- 
paratively deep waters of the glacial sea, to the estuary of the 
ancient Clyde; and their evidence corresponds with that of the 
Norwegian beds, in emphasizing the quiet and gradual nature of 
the successive steps. 
The elevation of the land, which took place during this period, 
has left its record in the existence of fossil beds, both of deep sea 
and of littoral character. In the island of Barholmen, off Drébak, 
a remarkable instance occurs. A fossil bank, reaching from the sea 
level to the height of 20 or 30 feet, contains a wonderful and 
peculiar deep-sea fauna. Oculina prolifera is abundant, a coral 
which, Sars states, is found on the north and west coast of Norway, 
but never at a less depth than from 150 to 300 fathoms. A clear 
proof of the elevation of the land to the extent of, at least, 800 feet, 
is thus obtained. The argument is strengthened by the association 
with Oculina prolifera of both mollusca, entomostraca, and forami- 
nifera, characteristic of great depths of water. Lima excavata is 
found, abundant, and of very large size, together with Pecten vitreus 
and Pecten aratus. 
At the summit of this island, a height of about 100 feet, a fossil 
bank also appears. This contains fragments of Oculina and a few 
of the shells common in the shore bed, but they are associated with 
littoral species. Littorina littorea, eg., is most abundant, and com- 
pletely characteristic of the deposit. 
The upper and the lower banks on Barholmen thus belong to 
the same age, but the one is littoral in its character, and the other 
must have been uplifted from beneath a very great depth of water. 
In these beds at Barholmen, the peculiar species of the older 
