1 88 1.] Scepticism in Geology . 331 
elusion that the metals, as a rule, expand, and certainly do 
not contract, in solidifying. 
Mountains in all parts of the world are split through to 
allow rivers to pass, observes “ Verifier,” and he instances 
the Litany, a river of Palestine, which if left to itself, ac- 
cording to the laws of Hydrostatics, — instead of cleaving 
the Lebanon to a depth of 600 feet, in places not more than 
10 or 15 feet wide, — must have followed the lower opening 
presented to it, and passed into the Dead Sea. He asks, 
“ Why should the Avon on quitting Bristol have altered its 
course, and, instead of running straightforward over the low 
ridge of Bedminster into the Bristol Channel, have turned 
north to encounter hills five times higher (400 to 500 feet), 
those of Leigh Downs, unless it had found the gorge of 
Clifton opened ready for it?” He argues that the gorge 
must have been produced by a “ great convulsion,” because 
the strata at one place has suffered a vertical displacement 
of 800 feet above those of the other. I would say that it 
has resulted from internal expansion consequent upon 
growth, and I can show him a precisely similar “ convulsion,” 
on a small scale, as the effeCt of growth upon the bark of a 
pear tree. The “ upheaval ” on one side of the crack, in 
the latter case, is indeed relatively much greater when the 
size of the trunk of the tree is compared with that of our 
globe. “Verifier” is more successful in suggesting that, 
when ravines have the strata on one side either lifted higher 
or sunk lower than those on the other, such phenomena 
cannot have been produced by the erosion of rivers, but are 
undeniably faults or fractures in the strata. 
From the foregoing it will be evident that the author of 
“ Scepticism in Geology ” attaches much less importance 
than is usually assigned to denudation in connection with 
the present conformation of the surface of the Earth. His 
criticism, it may be objected, assumes an unwarranted degree 
of severity, especially when considered in connection with 
the rival theory which he propounds in substitution of 
“ modern causes.” “ It is surely time,” he exclaims, “ that 
common sense should be exercised to resist the fallacy that 
weather, frost, ice, and running water (such as we now 
experience), could have carved out mountains, dug valleys, 
swept away piles of strata miles high, or strewed hills, 
valleys, and plains, all over the world, with streams of loose 
stones, including boulders as big as a house, gravel, clay, 
and earth. The reliance of modern Geology upon such 
feeble and inadequate agencies to produce such enormous 
results may perhaps be accounted for by the faCb that a 
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