216 Dr Fleming on the Geological Deluge. 
in furious motion. A few look to a sudden change in the Earth’s 
axis as the origin of the catastrophe, in the absence of all proof 
from the science of Astronomy. Some consider the waters as 
having been set in motion by the attractive force of a comet, with- 
out previously gaining an affirmative answer to the question, 
Has a comet this attractive force ? There is abundant proof 
that the planets disturb the comets, but the converse is not known. 
The comet of 1454 eclipsed the Moon ; while that of 1770 not 
only came near the Earth, but passed through the midst of the 
satellites of Jupiter, without producing any sensible effects. 
Others, translating the phrase of Moses, 44 the windows of Hea- 
ven,” as literally meaning 44 a comet’s tail,” have considered the 
water as added to the Earth. I would be disposed, before ad- 
mitting this view of the matter, to ask, Is the vapour of a co- 
met’s tail aqueous ? — The following phenomena, however, bear 
more directly upon the question under discussion. 
1. Excavation of Valleys. — Valleys, in the opinion of the sup- 
porters of the diluvian hypothesis, may have been produced by 
different causes, such as irregularity of deposition, or subse- 
quent dislocations of the strata. But those which exist in rocks 
nearly horizontal, 44 must be referred exclusively to the removal 
of the substance that once filled them ; and the cause of that re- 
moval appears to have been a violent and transient inundation.” 
Valleys of this kind have been designated by the very inap- 
propriate term, 44 Valleys of Denudation,” as if they had been 
only exposed , not formed , by the catastrophe. Many circum- 
stances seem to oppose the diluvian hypothesis, in reference to 
the origin of valleys ; among which, the following may be no- 
ticed. 
a. Shape of Valleys. — The valleys of denudation are not al- 
ways straight in their course ; they have their salient and re-en- 
tering angles, their lateral branches, and their increase in width 
as they descend. When we look at a valley, at present forming, 
by the action of running water, in beds of clay or gravel, we 
witness the sinuosities of its banks produced by the oscillations 
of the stream at the bottom , now transporting the materials from 
one side, then from another, and thus aiding the force of gravity 
3 
