£18 Dr Fleming on the Geological Deluge . 
ment for a geologist. But we may make an approach to the 
subject. When a river is in a violently flooded state, we wit- 
ness it remove the soil which opposes its current, transport to a 
lower level the loose blocks of rock, and sweep away the animal 
and vegetable productions occurring in its course. But it is 
subject to certain limitations. Throughout its course, its velo- 
city is greatest at the surface and the middle of the stream, from 
which it diminishes toward the bottom and the sides, where it is 
least. When it enters a hollow, lake or mill-pond, the water 
below the outlet has its motion checked, and, in its state of com- 
parative stillness, permits the heavier materials it had transported 
to subside. When a water-spout descends almost in a solid co- 
lumn of great height, and exerting, consequently, a pressure 
well calculated to remove obstructions, it penetrates the soil, and 
disperses it, along with the vegetable covering, removes the loose 
blocks of stone, and the surrounding detritus, while it makes 
but a feeble impression on the solid rock. When an alpine lake 
bursts its barriers, it acts precisely as a river in a flooded state ; 
carries along with it soil, loose rocks, trees and animals, deposit- 
ing at a lower level the wrecks of its course, — as happened in 
the Val de Bagnes, by the bursting of the lake of Mauvoisin, 
(Edin. Pliil. Journ. No. 1. p. 190.) 
Let us now suppose a body of water (no matter at present 
whether fresh or salt), of sufficient height to cover the highest 
mountains, and possessing a progressive motion of great velocity, 
suddenly to arive at the north of Zetland, traverse the kingdom, 
and pass off towards the south, at the Land's End, What would 
be the accompanying phenomena ? The soil would be every 
where annihilated in its progress, and, as mud, transported to a 
distance. The animal and vegetable inhabitants would be floated 
off. All detritus, boulders, and loose blocks of rocks, would, at 
the onset, yield to its pressure and velocity. But every lake, 
every valley, every lee side of a hill, every frith and bay of the 
sea, would speedily be in a state of comparative stillness, and 
receive the largest and the heaviest of the transported blocks. 
In the bottom of valleys and lakes we should now find the wreck 
of the catastrophe. But, have we the shadow of evidence to 
warrant the conclusion, that this inundation could tear up solid 
rocks, and make excavations in undisintegrated strata? No. 
