410 



SCIENCE. 



[N. S. Vol. I. No. 15. 



Ehine flowed across this land. A temperate 

 flora, mucli like that now existing in Eng- 

 land, prevailed; and among the land animals 

 were elephants, hippopotami, rhinoceroses, 

 horses, bison, boar, deer, machterodus, 

 hysena, wolves, glutton, bear, beaver, etc. 

 In other parts of Europe similar genial con- 

 ditions prevailed. A luxuriant deciduous 

 flora occupied the valleys of the Alps, at- 

 taining heights greater than the present 

 limits of the same vegetation. Elephants 

 existed with the flora in northern Italy. 

 From the amount of river-erosion effected 

 during this epoch it would appear that the 

 stage was one of long duration. 



4. Second or Maximum Glacial Epoch. — The 

 mountains of Scandinavia seem to have been 

 the center of dispersion of the ice at this 

 time, and the glaciers extended easterly so 

 as to become confluent with the Ural sys- 

 tem in western Siberia, southwesterly into 

 the basin of the Volga, southerly into the 

 basin of the Dnieper, Poland, Saxony, Bel- 

 gium, southwesterly to the British Islands, 

 excepting a small part of southern England, 

 and to the westward 600 feet below the 

 present surface of the Atlantic ocean, from 

 off Ireland to the Arctic sea. Both the 

 Baltic and North seas were covered by ice, 

 and erratics from the Scandinavian hills 

 were strewn more or less over this entire 

 area. They were also transported from 

 lower to higher levels in the British islands, 

 to a height of 3500 feet in Scotland, and the 

 highest peaks may have projected through 

 the ice as Nunatakker, like the bare spots 

 thus designated in Greenland. This area 

 is rudely elliptical in shape, 2700 miles long 

 and 1600 miles wide. In Switzerland the 

 Alpine glaciers reached their greatest exten- 

 sion, the snow line extending 4700 feet 

 lower than it is at present, the ice being 

 4000 feet thick in the low grounds, and im- 

 mense blocks of stone were carried across to 

 the Jura Mountains to an elevation of 3099 

 feet above Lake G-eneva. In connection 



with the presence of this ice, Arctic- Alpine 

 plants and animals occupied the lowgrounds 

 of Europe, extending even to the Mediter- 

 ranean. This epoch constituted the begin-, 

 ning of the pleistocene or quaternary period. 



5. Second Interglacial Epoch. — The return 

 of the temperate flora and fauna in north 

 Germany and central Russia is suggestive 

 of a milder and less extreme climate than is 

 now experienced in those regions. Britain 

 must have been connected with the conti- 

 nent and Italy with North Africa. The 

 rivers of this epoch eroded their valleys to 

 great depths. 



6. Third Glacial Epoch. — An extensive 

 ice-sheet overwhelmed most of the British 

 Islands and much of the continent. The 

 northwestern limits are much the same in 

 the edges of the Atlantic and Arctic oceans, 

 but to the east it extended about a hundred 

 miles beyond St. Petersbui'g, and just 

 reached Berlin to the south. From the 

 Alps glaciers descended to the low grounds, 

 dropping conspicuous moraines, which ex- 

 tend in curving lines between the highly 

 denuded moraines of the earlier epochs, 

 and the associated extensive fluvio-glacial 

 gi-avels. 



7. Tliird Interglacial Epoch. — The young- 

 est interglacial beds of the Baltic coast- 

 lands belong here, with both arctic and tem- 

 perate marine faunas — as the mammoth, 

 wooly rhinoceros, hare, urus and Irish deer. 

 It is probable that a considerable portion of 

 the old alluvial deposits of -Britain and Ire- 

 land, hitherto classed as post-glacial, belong 

 here. 



8. Fourth Glacial Epoch. — The ice-sheets 

 of the British Islands are now local and 

 entirely separate from the Scandinavian 

 mass. In Scotland the snow line did not 

 exceed 1600 feet in elevation above the sea; 

 the land was 100 feet higher than now, 

 and an arctic marine fauna occupied the 

 coasts. The Scandinavian peninsula sup- 

 ported an ice-sheet of more importance, 



