Southern Hemisphere. 
327 
1877.] 
Virginia on the other. The real markings on the rocks, 
however, have not been traced in Europe farther south than 
51 0 N. lat., and in America than 40° N. lat., excepting those 
of the ice that proceeded from the mountain ranges. 
In the other hemisphere, within the distance from the 
Southern Pole that the ice has been shown by adtual 
markings on the rocks to have reached from the North Pole 
on the European coasts,— -that is, to latitude 51 0 N., — there 
are no large masses of land, excepting the extreme end of 
South America and the Antarctic continent. And if we take 
a corresponding circle in the south to the limit the ice has 
left its marks in America or to lat. 40°, we shall still only 
embrace Patagonia in South America and the Middle Island 
in New Zealand. Even if we take the furthest limit of the 
extension of the Atlantic ice, as shown by its interference 
with the drainage of the American continent, we only bring 
South America as far north as the Rio Plata, and New 
Zealand and Tasmania, with the southern end of Australia, 
within the area where we could expedt to find any similar 
evidence on the supposition that in the Glacial period the 
ice extended everywhere as far from the Southern Pole as 
its extreme limit reached from the Northern. 
The conditions are therefore very different in the two 
hemispheres. In the one, broad continents stretch from 
within the Ardtic circle toward and up to the Equator ; in 
the other, nearly the whole of the temperate zone is covered 
with water. If, then, there were much less evidence than 
there is of the glaciation of southern lands, we need not 
have been surprised ; but of late there seems to have arisen 
an idea amongst some geologists that there is no evidence 
in the southern hemisphere of the occurrence of a Glacial 
period, and it may be useful if I bring together what has 
been described, and show how far the phenomena agree 
with those of the northern hemisphere. 
Commencing in America, immediately south of the 
Equator, we have first to deal with the remarkable theory 
of Agassiz, that the great valley of the Amazon was . once 
filled with ice flowing from the distant Andes, which left an 
enormous terminal moraine on the Atlantic coast. This 
moraine he supposed blocked up for a time the waters of the 
great valley, and caused the deposition of various stratified 
deposits covered by a peculiar drift clay that rarely contains 
transported boulders. I have examined this deposit from 
Pernambuco northwards through the provinces of Ceara and 
Maranham, as far as Para. In some parts it is composed of 
small angular fragments of rock, cemented together by an 
