J. Croll—Cause of Mild Polar Climates. 147 
the sea. ~ That glaciers from the southern Alps actually 
teached to the sea, and sent adrift their icebergs over what are 
how the sunny plains of Northern Italy, is proof that during 
that cold period the climate must have been very severe. 
glaciation was the result of eccentricity, is the fact that the bed 
's wholly destitute of organic remains while they are found 
abundantly both in the underlying and overlying beds. 
vidence of glaciation during the Eocene period, as is also 
Well known, is found in the “flysch” of Switzerland. On the 
north side of the Alps, from Switzerland to Vienna, and also 
neat Genoa, there is a sandstone a few thousand feet in thick- 
ness, containing enormous blocks of Oolitic limestone and 
Pranite. Many of these blocks are upwards of 10 feet in 
length, and one at Haelkeren, near the Lake of Thun, is 105 
et long, 90 feet broad, and 45 feet in thickness. The block © 
'S OL a granite of a peculiar kind which cannot be matched 
Which have a decided tropical aspect. This is what we ought, 
Course, d prior?, to expect if the glaciation was the result of 
~ chtricity, for the more severe a cold period of a a 
Pech is, the warmer will be the periods which immediately 
Preeede and succeed 
