April 1-2, 1893.] 



SCIENCE. 



411 



which discharged icebergs at the mouths of 

 fiords in western Norway. Finland was 

 overwhelmed, and the Baltic basin was 

 occupied by a great ice stream, which in- 

 vaded north Germanj- and Denmark. As 

 the ice melted, a wide area in Scandinavia 

 was submerged in a cold sea communica- 

 ting with the Baltic. In the Alps the snow 

 line was 300 feet lower than now. 



9. Fourth Inter<jlacial Epoch. — The British 

 Islands were connected with the continent. 

 Deciduous trees spread far north into re- 

 gions now bereft of them. The Baltic sea 

 became converted into a great lake ; Den- 

 mark and Sweden were united ; the Rhine 

 flowed quite near England and Scotland, 

 over the upraised bed of the North Sea, 

 meeting the main ocean above Bergen; the 

 Seine flowed through the English channel 

 l)eyond Brest, and there was a large river 

 flowing over the bed of the Irish Sea, hav- 

 ing the Severn for a ti'ibutary, and meeting 

 the ocean quite near the mouth of the 

 Seine, and there was a land connection be- 

 tween the continent, Great Britain, Iceland 

 and Greenland. When the salt water fin- 

 ally returned, the fauna was more temper- 

 ate than it is at present. This epoch is not 

 yet recognized in the Alps. 



10. Fifth Glacial Ej^och.— In Scotland the 

 snow line reached an average height of 

 2,500 feet, the shore line being fiftj' feet 

 lower than it is now. Occasionally glaciers 

 discharged bergs into the sea on the north- 

 west coast of Scotland. Most of the corrie 

 rock-basins of the British Islands were ex- 

 cavated in this epoch, each one marking the 

 presence of a distinct glacier. In the Alps 

 there were advances of the glaciers giving 

 rise to terndinal moraines, the snow line 

 reaching a depression of 1 ,600 feet below the 

 present limit. 



11. Fifth Interglacial Epoch. — The upper 

 ' buried forests ' of northwest Europe show 

 that this epoch was characterized by drier 

 conditions and a remarkable recrudescence 



of forest gro\\i;h. It is uncertain whether 

 Britain was connected witli the continent. 



12. Sixth Glacial Epoch. — This is indicated 

 by the latest raised beaches of Scotland, 

 indicating twenty or thirty feet of depres- 

 sion. The snow line stood at an elevation 

 of 3,500 feet, and thus a few small glaciers 

 could exist in the loftiest highlands. In the 

 western Alps there were some high level 

 moraines. 



13. The Present. — The sea has retreated 

 to its present level, drier conditions prevail 

 and permanent snow fields have disai)peared 

 from most of the regions in northern Europe 

 once so comj)letely submerged by glacial 

 ice. The term post-glacial properly de- 

 scribes only the present epoch. 



Professor Geikie' devotes three chapters 

 to a discussion of the presence of man in the 

 Pleistocene. His bones and implements 

 are found chiefly in the extra-glacial regions, 

 associated with the remains of both extinct 

 and living mammalia, such as have been 

 mentioned as occurring in several of the 

 interglacial epochs. Man would naturally 

 migrate towards the glaciers as they receded, 

 and retreat southerly as they advanced. 

 The large animals would have done the 

 same ; hence a perfectly satisfactory corre- 

 lation of the several teiTanes in the glaciat- 

 ed and extra-glacial regions is of difficult 

 attainment. Our author concludes that 

 Paleolithic man existed abundantly in the 

 second interglacial epoch in company with 

 the elephas antiquus and hippopotamus. 

 Some of the caves occupii^d by him appear 

 to have been abandoned before the third 

 glacial epoch reached its climax, because 

 thej' are sealed up by the moraines of that 

 stage. During this epoch Paleolithic man 

 seems to have retired to southern France, 

 and, if negative evidence is of value, he 

 never revisited northwestern Europe. 



American geologists will be more than 

 pleased with the sketch of the glacial phe- 

 nomena of North America by Prof. Cham- 



