328 Glacial Period in the [July, 
ochraceous clay, and resembling the brecciae at the base of 
the Permian rocks in Westmoreland. In others it is a fer- 
ruginous clay, containing few stones, but with a layer of 
quartz pebbles at its base. It is not confined to the valleys, 
but wraps over the hills like a mantle. Now and then it 
contains large boulders of granite, but I could never satisfy 
myself that these might not have been left during the 
decomposition and denudation of the rocks of the neigh- 
bourhood. It differs much from any glacial deposit I have 
seen, and I am sorry that I can neither suggest any theory 
to account for its origin nor agree with that of the illustrious 
Agassiz. To the latter there seems to me insuperable ob- 
jections. There are no moraines in the valley of the Lower 
Amazon. The terminal one might have been, as Agassiz 
suggests, washed away by the waves of the Atlantic, but the 
great glacier ought to have left others to mark the various 
stages of its recession. No remnant of these has been 
found, and we cannot believe that a glacier that left a huge 
moraine stretching for hundreds of miles across the whole 
seaward front of the Amazon Valley should have shrunk 
back for more than 1000 miles without leaving any what- 
ever to mark its retreating course. The Valley of the 
Amazon abounds with birds and beasts, many of which are 
found nowhere else. Peculiar species of fishes swarm in 
the river and its tributaries. If the great valley was filled 
with ice, where did these find a refuge ? To Agassiz this 
did not present any difficulty, as he believed that the present 
inhabitants of the world had been created since the Glacial 
period ; but to those who hold the opinion that they are 
descended from pre-glacial ancestors, and that since the 
Glacial period there has not been much variation, the pecu- 
liar genera and species of the fauna of the Amazon Valley 
present serious objections to the theory. 
Had Agassiz found in the Valley of the Amazon what he 
considered moraines, I should have had much difficulty in 
believing that he was mistaken, for no man had more expe- 
rience of ice-aCtion, present and past. Before him, Char- 
pentier and others had worked out the conclusion that the 
glaciers of the Alps had in former days stretched far beyond 
their present limits, but they referred that extension to an 
elevation of the mountains, and not to a change of climate 
that affeCted all the northern parts of the continent. Agas- 
siz accepted the theory, at first, that the upheaval of the 
Alps must, in some way or other, have been connected with 
the phenomena, but further study led him to abandon it, 
and conclude that the climatic conditions could not have 
