71 
being also concluded, no further production of sulphuretted 
hydrogen, or formation of metallic sulphurets, could take 
place. The rocks would now become dry and permeable to 
atmospheric air, which by this time would have become rich 
in oxygen and poor in carbonic acid, by the immense quantity 
of the latter which was decomposed and deposited, in the 
coal series. This oxygen would now act upon the portion 
of animal matter which had escaped the putrefactive decom- 
position, and a true process of oxidation, or decay, be estab- 
lished through the whole mass. Nor would this oxidation be 
confined to the organic matter alone : the metallic ores them- 
selves would share the same fate, and in place of sulphurets 
we should have sulphates — in place of protoxides, peroxides 
or carbonates. New chemical agencies, therefore, began to 
operate and to pull down the fabric which had just been 
raised, and, shortly, a state of things occurred similar to 
what we observe at the present day. 
It must be observed that the decay of these animal remains 
is an abundant source of carbonic acid gas, and this being a 
process now in operation, we are able to account for the 
large quantity of carbonic acid existing in spring water 
issuing from such rocks at the present day. As water con- 
taining this acid has the property of dissolving carbonate of 
lime, we may easily conceive that these rocks contain the 
elements of their own destruction. That they are, in fact, 
gradually dissolving away, and furnishing materials for the 
construction of new ones at the bottom of our present seas, 
is fully proved by the presence of a large quantity of car- 
bonate of lime in all the springs issuing from such rocks, 
and in the rivers which they supply ; although the proportion 
may be small as represented by a chemical analysis, amount- 
ing, on the average, to about ten grains per gallon, yet, 
when we consider the immense quantity which flows along 
most of our large rivers, it becomes immeasurably great. 
