Hooker saw maize growing on ancient and gigantic
moraines. Southward of the Asiatic continent, on the opposite side of the
equator, we know, from the excellent researches of Dr. J. Haast and Dr.
Hector, that in New Zealand immense glaciers formerly descended to a low
level; and the same plants, found by Dr. Hooker on widely separated
mountains in this island tell the same story of a former cold period. From
facts communicated to me by the Rev. W.B. Clarke, it appears also that
there are traces of former glacial action on the mountains of the south-
eastern corner of Australia.
Looking to America: in the northern half, ice-borne fragments of rock have
been observed on the eastern side of the continent, as far south as
latitude 36 and 37 degrees, and on the shores of the Pacific, where the
climate is now so different, as far south as latitude 46 degrees. Erratic
boulders have, also, been noticed on the Rocky Mountains. In the
Cordillera of South America, nearly under the equator, glaciers once
extended far below their present level. In central Chile I examined a vast
mound of detritus with great boulders, crossing the Portillo valley, which,
there can hardly be a doubt, once formed a huge moraine; and Mr. D. Forbes
informs me that he found in various parts of the Cordillera, from latitude
13 to 30 degrees south, at about the height of 12,000 feet, deeply-furrowed
rocks, resembling those with which he was familiar in Norway, and likewise
great masses of detritus, including grooved pebbles.
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