31 
and icebergs played a conspicuous part, when large boul- 
ders of rocks of all ages were carried by ice and water 
from all parts and scattered far and wide over the surface. 
This state of unusual cold was abnormal, for up to the 
glacial epoch the general climatal conditions were those 
of considerable heat, if not absolutely tropical, which 
more or less prevailed during the deposition of the great 
formations which constitute the widely-extended ages of 
the Tertiary, Secondary and Paleozoic divisions of Geo- 
logical time, long anterior to the existence of man. 
Passing over the numerous and widespread formations 
not represented in this county, we come to that of the 
Lias. The varying alternating masses of limestone, clay, 
and shale were deposited in seas of variable depth, at 
greater or less distance from land, in which, as might be 
expected, marine fossils of many extinct genera, Saurians, 
fish, shells, and some corals predominate. The Enalio- 
saurians were of large size, predaceous, and aquatic. 
Among the shells the most remarkable were the great 
cephalopodous Mollusks, Ammonites, Belemnites, and 
Sepia, which swarmed in the Liassic sea, and like the 
Saurians, acted as the scavengers of the ocean. In some 
portions of this formation the land appears to have been 
remote, but in others much nearer, for we have many 
genera of terrestrial plants, and in the lower division a 
large number and variety of insects, whence it may be 
fairly inferred that other forms of life inhabited the land, 
mammalia and other classes, which have yet to be dis- 
covered by some future fortunate paleontologist. 
The Rhetic period which succeded, to whatever age it 
may be assigned, is rich.in marine remains, presenting 
many local and peculiar forms of conchifera and mollusca, 
many of which occur in this county, and more no doubt 
would be obtained if the strata were sufficiently exposed, 
which they unfortunaly are not. 
