342 
with satisfactory clearness the distinct character and the 
opposite mode of production of these two classes of mineral 
formations. We have all the evidence that can reasonably be 
desired of the previous condition of those underlying rocks, 
their ancient, and, at a depth not great, their present liquidity 
by heat; their boiling up ; their extrusion, both m the melted 
state and in different degrees of advancement towards being 
cooled and hardened; their being driven upward through the 
overlying formations of deposited layers ; their sometimes 
insinuating themselves between the previously contiguous 
surfaces of those deposits; their filling long furrows of 
outbursts, and their being laid bare in many cases to open 
davlight. It is therefore no presumption to affirm that we 
do know, with the clearness of sensible evidence, the con- 
stituent formations of the crust of the earth, them Modes o 
production, their relations to each other, and the fact of their 
enveloping a mass of materials similar in composition to the 
lowest rocks, and which we have much reason to think are, at 
certain depths, still in a state of constant fusion. * What does 
the editor of the Geological Magazine for 1865 say to this 
“certain” and almost “perfect” knowledge? His words 
are: “Many a range of so-called primeval granite, gneiss, 
and" slate, lapping the one over the other successively tor 
hundreds of thousands of feet, or of upright primary 
schistus ’ miles across, will exhibit to the geologist of to-day 
only many-times-repeated folds of an altered set of strata , 
nor will their furthest change, or granitic form, betaken either 
for primeval or intrusive granite : and whilst the fatter may 
still be found, the former, or the hypothetical granite ot a 
cooling globe, becomes a myth ”f Sir Charles Lyel ex- 
presses the same truth still more decidedly. In the firs., 
volume of his “ Principles,” which has just been issued, he 
says, “The progress of geological investigation gradually 
dissipated the idea, at first universally entertained, that the 
granite or crystalline foundations of the earth s crust were o. 
older date than all the fossiliferous strata. It has now been 
demonstrated that this opinion is so far from the truth that it 
is difficult to point to a mass of volcanic or plutomc rock 
which is more ancient than the oldest known organic remains. 
So the all but perfect knowledge of the excellent man who 
felt, in view of it, that our Scriptural cosmogony must be a 
recast, was only a perfect delusion ! Are we not taught by 
this that great minds are not only gigantic m then g P 
* Dr. J. Pye Smith’s Scripture and Geology, edition 1843, pp- 44 to 46. 
t Geological Magazine for January, 1865, page 2. 
X Lyell’s Principles of Geology, edition 1867, m loco. 
