THE GLACIAL PERIOD. 169 



CHAPTEE X. 



THE GLACIAL PERIOD. 



Early views of glacial phenomena — Agassiz's glacial theory — Glacial phenomena 

 of Scotland —Origin of rock-strise, roches montonnees, till or bonlder-clay, etc. 

 — Intruded till and great erratics — Direction of glaciation in Scotland — 

 Glaciation of Ireland ; of English Lake District ; of Lancashire ; "Wales, etc. 

 — Glacial phenomena of north-east of England ; of Midland districts and East 

 Anglia — Great erratics — Glaciation of Norway and Sweden ; of Finland and 

 Northern Russia ; of Germany — Contorted and disturbed rocks under boulder- 

 clay — Great erratics — Direction of the northern mer de glace — Course followed 

 by "under-tow" of ice-sheet. 



Throughout vast areas in the low grounds of Northern Europe, 

 and in all the mountain-tracts of the central and southern regions 

 of our continent, we encounter the clearest and most abundant 

 evidence to show that a much severer climate than the present 

 has formerly obtained. I have already adduced a number of 

 facts which must have convinced the reader that towards the 

 close of the Palaeolithic Age the ancient inhabitants of Aquitaine 

 lived under conditions such as now characterise only the higher 

 latitudes. When the temperature in Central and Southern 

 Europe was so depressed as to allow reindeer and musk-sheep to 

 live in the low grounds that sweep north from the base of the 

 Pyrenees, and the glutton, the marmot, and the tailless hare to 

 frequent the shores of the Mediterranean, what, we may well 

 ask, must have been the condition of those tracts to which these 

 animals are now restricted ? Fortunately we are able to give a 

 very definite reply to this question. The evidence brings before 

 our vision scenes that are in strangest contrast to the present — 



