entury after Hutton
propounded it; nor did it begin to gain general currency until Lyell's
crusade against catastrophism, begun about 1830, had for a quarter of a
century accustomed geologists to the thought of slow, continuous changes
producing final results of colossal proportions. And even long after
that it was combated by such men as Murchison, Director-General of
the Geological Survey of Great Britain, then accounted the foremost
field-geologist of his time, who continued to believe that the existing
valleys owe their main features to subterranean forces of upheaval.
Even Murchison, however, made some recession from the belief of the
Continental authorities, Elie de Beaumont and Leopold von Buch,
who contended that the mountains had sprung up like veritable
jacks-in-the-box. Von Buch, whom his friend and fellow-pupil Von
Humboldt considered the foremost geologist of the time, died in 1853,
still firm in his early faith that the erratic bowlders found high on
the Jura had been hurled there, like cannon-balls, across the valley of
Geneva by the sudden upheaval of a neighboring mountain-range.
AGASSIZ AND THE GLACIAL THEORY
The bowlders whose presence on the crags of the Jura the old Gerinan
accounted for in a manner so theatrical had long been a source of
contention among geologists. They are found not merely on the Jura,
but on numberless other mountains in all north-temperate latitudes, and
often far out in the open country, as many a farmer who has broken his
plough against them might testify. The early geologists accounted for
them, as for nearly everything else, with their supposititious Deluge.
Brongniart and Cuvier and Buckland and their contemporaries appeared
to have no difficulty in conceiving that masses of granite weighing
hundreds of tons had been swept by this current scores or hundreds
of miles from their source. But, of course, the uniformitarian faith
permitted no such explanation, nor could it countenance the projection
idea; so Lyell was bound to find some other means of transportation for
the puzzling erratics.
The only available medium was ice, but, fortunately, this one seemed
quite sufficient. Icebergs, said Lyell, are observed to carry all manner
of debris, and deposit it in the sea-bottoms. Present land surfaces
have often been submerged beneath the sea. During the latest of these
submergences icebergs deposited the bowlders now scattered here
and there over the land. Nothing could b
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