climate of Nortliern Italy, and to tlie fact that gigantic moraines 
of old glaciers are now clothed by the vine and maize, and 
Swiss geologists have found Alpine blocks far down into the 
plains of Lombardy. Still, travelling south and crossing the 
Mediterranean into Africa, there Dr. Hooker found evidence 
of ancient glaciers in the Atlas Mountains, and Mr. G. Mawe, 
who travelled with him, said of the old moraines he there met 
with, they tend to confirm the opinion entertained by many 
geologists that the refrigeration during the Glacial period was 
almost universal.^^* * * § A little further south. Sir Charles Lyell 
is my authority for saying that in one part of the Glacial 
period the desert of Sahara was under water between latitude 
30° and 20° [a breadth of nearly 700 miles], so that the 
eastern part of the Mediterranean communicated with that 
part of the ocean now bounded by the west coast of Africa.^^t 
Any farther retreat of the mammalia southward on the African 
continent would have been effectually cut off. 
15. We may have to wait for years for a full geological 
survey of Asia, but the evidence we have on this subject is in 
harmony with that of Europe and Africa. Boulder drift was 
found by Dr. Hooker on Mount Lebanon,]; and its celebrated 
cedars growing upon ancient glacial moraines, whilst Mr. 
Gifford Palgrave met with vestiges of the Glacial period in the 
neighbourhood of the upper Euphrates. And along the range 
of the Himalaya, at points 900 miles apart, Mr. Darwin says 
that glaciers have left their marks of former low descent. 
16. We will now leave the Eastern Hemisphere, and see 
how the evidence stands on the Western. From the report of 
the geological survey of Illinois, we learn that this State, ex- 
tending from 42° to 35° N. lat., with an area of 55,000 square 
miles has its undulating prairies, everywhere covered with ice 
drift, leaving unmistakable evidence that flotillas of icebergs 
have made their way across its extended plains. This corre- 
sponds with what Professor Hitchcock said many years ago of 
Massachusetts. His words are : '^The conclusion to which I have 
been irresistibly forced by an examination of this stratum in 
Massachusetts is, that all the diluvium which had been accu- 
mulated by various agencies has been modified by a powerful 
deluge sweeping from the north and north-west over every 
part of the State, not excepting its highest mountains. § I 
need not remind you of the law by which water finds its own 
* Dawkins’ Cave Hunting, p. 387. Quoted from A Journey to Morocco, 
t Lyell, Principles of Geology, 11th edition, p. 253. 
+ Hooker, Natural History Beview, p. 12, 1861. 
§ Geology of Massachusetts. 
