Electronic edition published by Cultural Heritage Langauge Technologies (with permission from Charles Scribners and Sons) and funded by the National Science Foundation International Digital Libraries Program. This text has been proofread to a low degree of accuracy. It was converted to electronic form using data entry.
SCROPE, GEORGE JULIUS POULETT (b. London,
England, 10 March 1797; d. Fairlawn [near
Cobham], Surrey, England, 19 January 1876), geology.
of James Hutton, John Playfair, and James Hall,
but Scrope's restatement in combination with the
theory of a cooling earth was to provide the basis
for a catastrophist opposition to the uniformitarianism
of Lyell.
Scrope's second book, Memoir on the Geology
of Central France (1827, but written in 1822), was
more uniformitarian in approach, being devoted to
a small region during geologically recent times.
Improving upon the work of French geologists in
Auvergne, he showed that currents of lava, which
had flowed into valleys at various times, appeared
at different heights above the river beds, marking
successive steps in the progress of erosion of the
valleys by the rivers. Scrope refuted the arguments
for a recent deluge in the region and showed the
untenability of attempts to classify the volcanic
cones into antediluvian and postdiluvian on the
basis of the amount of erosion they had undergone.
As additional evidence that rivers are capable of
producing impressive valleys unaided by a deluge,
he cited in 1830 the presence of entrenched
meanders in the valleys of the Meuse and Moselle.2
These arguments were effective in undermining the
Cuvier-Buckland theory of a recent universal
deluge, identical with the Biblical flood, that had
deposited debris and had carved the major valleys.
The theory was eventually abandoned by its remaining
supporters in the Geological Society.
Scrope always believed that his two books had
greatly influenced the development of Lyell's uniformitarian
views; and Lyell's dependence is traceable
in two articles that he wrote in 1826 and 1827
for the Quarterly Review. The latter was a very
favorable review of Scrope's second book. Lyell
soon after verified Scrope's observations in central
France and Italy (1828-1829). Therefore, Scrope
can, paradoxically, be regarded as a parent of both
uniformitarianism and its catastrophist opposition
in Great Britain. He never committed himself to
either side and always occupied a middle ground.
As one of a number of younger geologists who
wished, as he expressed it, to free geology “from
the clutches of Moses,” Scrope assisted Lyell in
the completion of the first volume of his Principles
of Geology (1830), which had as a principal objective
the extermination of theological influence on
geology. A favorable review was ensured, since
the publisher also owned the Quarterly Review;
and its editor, after consulting Lyell, chose Scrope
as the reviewer. Scrope wrote the review with
Lyell's advice, and he also reviewed Lyell's third
volume for the same journal (1835). In these and
later reviews, Scrope argued strongly against religious
influence in geology, yet he asserted that
there was no conflict between the Bible and geology
and wrote enthusiastically about the great contributions
of geology to natural theology. He put
forth, in opposition to Lyell, the evidence for progressive
change in the histories of the earth and of
life; and he was unimpressed by Lyell's hypothesis
of a chemical source of heat within the earth.
Scrope rejected Lyell's metamorphic theory,
which asserted that the “stratified primary rocks,”
such as gneiss and schist, were normal sedimentary
rocks altered by internal heat. He contended
instead that the stratified primary rocks had originally
been disintegrated granite deposited in hot
agitated water when the primitive earth was hot
and barren.3 He later gave up this explanation but
continued to believe that the foliation of these
rocks was caused by differential movement.
Scrope regarded the earth as essentially solid in its
interior, kept in this state by intense pressure
brought about by the expansive forces of heat and
steam. The subterranean matter was thus in a state
of tension so that any slight reduction of external
pressure, caused perhaps by a change in atmospheric
pressure or by the tidal action of the sun
and moon, or an increase in internal temperature
brought about by a local influx of heat would be
sufficient to cause local melting accompanied by
fracturing of the surrounding rock and the penetration
of the fractures by the molten rock.
Scrope saw no essential difference between the
causes of volcanoes and of earthquakes; a volcano
was the result of fracturing at shallow depths,
which allowed the fluid material to reach the surface.
In 1856 he argued that this same cause could
also produce a violent fracture and elevation of the
overlying crust and the extrusion through a fissure
of a ridge of crystalline matter. As the central axis
of this protruded ridge or mountain range rose, the
hot and partially fluid matter on the sides would be
subject to friction, causing differential movement
and the formation of parallel striations. In support
of this theory he argued that mountain ranges typically
show granite in the center, passing on the
sides into gneiss (or “squeezed granite”) and, further
on, into schist.4
To the end of his life, Scrope continued to believe
in the possibility of rare cataclysmic earth
movements far in excess of anything that Lyell
would allow, although Scrope's early catastrophism
was soon modified to the extent that he believed
that a mountain range had been formed by a
succession of upheavals rather than by one grand
upheaval, as advocated by Élie de Beaumont.