22 JOURNAL AND PROCEEDINGS 



up, carrN'ing up rocks of this period from the sea-floor to 16,000 

 feet high. The generally warm climate indicated in former periods 

 now gradual]}' changed into modern conditions of graduated tem- 

 perature from tlie Equator to the poles. At the beginning of the 

 Cainozoic period the climate within the Arctic circle was mild, but 

 before its close it became so cold that snow and ice spread far 

 southward over Europe and North America. Plants and animals 

 are now strikingly modern. We may imagine meadows, wood- 

 lands and forests similar to those of the present day. The mam- 

 mals of this period reached a variety of type and magnitude of size 

 far surpassing that of the present day. Rocks now begin to be 

 studied with reference to the present day — hence names, Eocene, 

 Miocene, Pliocene, Pleistocene. The western plains were still un- 

 der water, but it changed from a sea water area to a fresh water 

 lake. During this period the entire West rose several thousand 

 feet by a slow oscillating movement, so that the land mass above 

 .sea level was increased at least tenfold. During this period also 

 there was great volcanic activity shown by immense peaks and 

 masses of lava scattered through the Cordilleran region from Mex- 

 ico to the Arctic. Along the shore of the Baltic in North Ger- 

 many 2,000 species of insects have been found in amber, a fossil 

 gum from ancient coniferous trees. The vertebrates form the great 

 feature of Cainozoic life. The majorit}' of fishes are like the food- 

 fishes of the present. Teeth of sharks are verj^ abundant in marine 

 deposits. The snakes of this period have interest because they are 

 degenerate forms, having lost the limbs which their ancestors pos- 

 sessed. Primitive whales occur in the sea deposits — one about 70 

 feet long being found in Alabama. The whale is also believed to 

 have degenerated from a mammal which lived on land. Miocene 

 beds in Western America contain .several representatives of carniv- 

 orous animals — the panther, dog, cat, wolf and tiger. Rodents be- 

 gan their hi.story in this period and were abundant before the Alps 

 were formed. Of the species of elephants the mastodon was of im- 

 mense size. The pig is found in the Eocene beds ; the earliest 

 oxen in the Pliocene ; camels also as far back as Eocene. The 

 earliest known horse is from the Eocene deposits and was about 

 the size of a fox. It had three toes on the hind feet and four on 



