ON THE DELUGE. 673 



Still there are some points but lightly touched, or unnoticed, 

 by any person whose works bearing particularly on this sub- 

 ject I have yet seen. One is the rapidity with which certain 

 substances combine under water, and form stone ; such, for 

 instance,* as those used in Roman cement: — another is the 

 possibility of fragile substances, such as shells, small creatures, 

 leaves, corallines, branches, &c., being enveloped in a muddy 

 matrix, while floating at various depths, according to their spe- 

 cific gravities ; and the precipitation (chemically speaking) or 

 consolidation, or simple deposition of such cohering masses.-f- 



The similarity of coal to asphalte inclines one to suspect 

 an identity of origin ; and that coal, in a fluid state, enveloped 

 quantities of vegetable matter — was for some time agitated by 

 the continual tides and tidal currents of the diluvial ocean, and 

 afterwards hardened by cooling, by pressure, or by chemical 

 cheaige ; if not by all three. We find the impressions of leaves, 

 stems, and branches — and even large woody trunks embedded 

 in coal : but that the matrix, in which the leaves were enveloped 

 and subjected to pressure, was not triturated vegetable matter 

 is probable, because the casts of delicate vegetable substances 

 found in it show few, if any, signs of friction or maceration. 

 The impressions are as beautifully perfect as those of shells 

 in fossils where the shell itself has disappeared. Might we not 

 as well say that limestone was formed out of decomposed or 

 pulverised shells, as assert that coal was formed out of the 

 luxuriant herbage, the ferns and the palms, of a former state 

 of the world ? 



Asphalte is at first buoyant; that trees and other vegetable 

 productions are so I need not remark; but coal sinks in water, 

 and asphalte may be altered chemically so as to sink like coal. 

 Experiments on the asphalte of the famous lake at Trinidad 

 have proved that there is so very close an analogy between that 

 substance and coal, that a gas, exactly resembling coal gas, and 



• Lyell, Elements of Geology, 1838, p. 75-6. 



t The simplest experiments with pulverised, or numerous minute 

 substances in water, shew that they attract one another mutually, and 

 then cohere. 



VOL. II. 2 X 



