NATURAL HISTORY MISCELLANY. 729 
can exceed the delicacy and finish of the figures.—Newman’s Ento- 
mologist. A 
GEOLOGY. 
Tue Drier Pertop.—In a paper read at the Lyceum of Natural 
History, New York Oct. 24, 1870, Prof. Newberry observed :— In 
the sequence of events included in our Drift period there is a 
marked break, a middle period, during which, over most of the 
north-western states, no Drift deposits were made, and when most 
of this area was covered with a forest growth and sustained many 
and large animals. At a subsequent period, all parts of this area, 
less than five hundred feet above the highest of our present great 
lakes was submerged, and most portions of it covered to greater 
or less depth, with new Drift deposits, clays, sands, gravel and 
boulders, a large part of northern and remote origin. Nearly all 
the large boulders of the Drift belonging to this later epoch are 
sometimes of great size (one hundred tons) and have been Jloated 
to their present positions, as they overlie undisturbed stratified 
sands and clays, which would have been broken up and carried 
away by glaciers or currents of water moving with sufficient ve- 
locity to transport these blocks. Hence they must have been 
floated from the Canadian highlands, the place of origin of most 
of them, by icebergs. This epoch of the Drift period I have there- 
fore termed the Iceberg Epoch. During this epoch the submer- 
gence of the land in the interior of the continent, was greater 
than in the epoch of the deposition of the Champlain and Erie 
clays, and all the area north of the Ohio was covered with water 
np to a height of over five hundred feet above Lake Erie, or one 
thousand one hundred feet above the ocean level. The highlands 
of south eastern Ohio, and most of the country south of the Ohio 
river were not covered by this flood and now bear no drift deposit 
of any kind. Tracing out the line of ancient water-surface, we 
find that the depression was greater towards the north, so that 
the Alleghanies and their foot-hills, and also a wide area of com- 
paratively low country in the southern states formed not only a 
shore, but a continental limit to the great interior iceberg-ridden 
sea of the later Drift Epoch. In the western reaches of this sea, 
which was of fresh water in the later centuries of its existence, 
was deposited the Loess or “ Bluff” which I have elsewhere desig- 
