Wernerian and Huttonian Systems of Geology. 
327 
embraces the most unexceptionable dogmas both of Hutton and Werner, — a theory 
which, in the words of Conybeare, “ admits of the operation of a volcanic agency 
beneath the pressure of an incumbent ocean, but which does not in any degree 
question tin' Neptunian origin of rocks, which have evidently been formed in the 
bosom of that ocean.” It is now very generally allowed, that the trap rocks are 
of volcanic origin, and many too give a similar origin to the granites : and while 
on this subject, I cannot but allude to an opinion which has been of late most 
ably supported, and in favor of which every day's experience is adding new facts. 
The supporters of the opinion just alluded to, contend that whole countries have 
been raised to their present elevated position, by some expansive force which operat- 
ed from below; and that the granites, more especially, have been upheavedin a solid 
firm, thro’ superimposed masses of overlying rocks. Supposing this theory to be 
true, we can easily conceive that that cause, which operated in elevating so large, a 
body of matter already formed, might have rendered fluid the strata, which, lying in 
an inferior position, it might first have acted upon, and that, too, under an enor- 
mous pressure. In this way, we might account for the circumstance that the true 
granites rarely occur stratified ; and in the same way, we might explain the pheno- 
mena of granite and porphyry veins, &c. &c. while the chemical constituents 
of of the granites, their mode of occurrence, their similarity, or rather identity, in point 
of of composition witli the gneisses, the circumstance, of their passing by insensible 
degrees into all the rocks with which they are associated, would aU seem to indi- 
cate that the cause which originally formed, what have been called, the primitive rocks, 
was one and the same. We might, in this way, reconcile Dr. Macculloch's theory of 
the igneous formation of the true granites with the appearances observed in nature. 
If the present elevated position of the granites he attributable to an expansive force 
which operated from below, at a period posterior to their first formation, I should also 
conclude, with some of our latest geologists, that this period must have been posterior 
to the formation of some of the newer marine deposites. I could adduce many in- 
stances from Indian geology in proof of such an opinion. 
The enormous extent of the few distinct formations as yet discovered in India, 
and the ease with which, in most instances, we can trace their limits, give us many 
advantages. The more recent of the supermedial rocks, the oolites, and chalks are, 
as far as we yet know, wanting in this vast continent ; and a characteristic feature 
in its geology, is the enormous extent of its lower granite tracts, many of them 
distinguished, though on a small scale, by all the wildness and ruggedness of out- 
line of an alpine country ; a circumstance which might, perhaps, he attributed to the 
absence of that superimposed weight of newer rucks, which might, in other countries , 
have presented an obstacle to the full operation of the supposed expansive force, espe~ 
dally in stick situations where ilt power was weakly exerted! while, among the Hima- 
laya mountains, we may suppose, that this force, operating without ojijiosition, and 
in all its energy, raised to their stupendous height the jHnnncles of our globe. But 
I have no room at present to indulge in such a discussion, and shall content my- 
self with remarking, that the fact alone, that many of the enormous masses of pri- 
mitive rocks, constituting entire countries, are skirted, or I may say, isolated, by 
newer formations corresponding exactly with each other, even at the greatest dis- 
tances, is a strong presumptive evidence, that the said primitive rocks were elevated, 
or rather, I ought to say, forced through a superjacent formation, the remains of 
which are still found skirting the mountainous countries which now occupy a cen- 
tral position in respect to such newer formations. The skirting belts of these newer 
rocks are frequently very narrow, and the above opinion is certainly a more rational 
one, than if we were to believe that so many local causes should have operated at one 
and the same time, and should have formed rocks precisely of the same nature, and 
characterised by the same kinds of organic remains : and that, too, in the different 
positions, often far distant from each other, in which such newer formations are 
found. 
I cannot conclude this, I fear too lengthened epistle, without alluding to the most 
interesting experiments of Sir .1. Hall, relative, to the influence of sea salt as an 
agent in causing the fusion and consolidation of the incoherent parts from which he 
supposes our newer rocks to have been formed ; and, in connexion with this sub- 
ject, it is worthy of remark, that the saliferous sandstone formation, to which his 
experiments in this case more, particularly refer,is almost always associated with the 
trap rocks, and, indeed, in some cases passes into them, and that, as before stated, 
the trap rocks are now pretty generally allowed to be of volcanic origin. The 
saliferous sandstones are characterised by a nearly total absence of organic remains, 
a circumstance which ought not to be lost sight of in considering this subject. 
