i76 ON THE TllAr-KOCKS IN YOIIKSHIRE, &C. 
is the true one, are placed deeper in the crust of the Earth 
than gneiss and other primitive rocks. But this Huttonian 
explanation is opposed, and with much ingenuity and force 
of argument, and detail of fact, by the Neptunians, who 
insist on the deposition of trap from aqueous solution 
and suspension. We do not pretend to advocate either 
opinion, but maintain, that these rival hypotheses have 
been eminently useful, and that, without their aid, geology 
would have long remained stationary. Can we believe 
those to be in earnest who assert, that opinions, which have 
been the means of calling into action the zeal and acuteness 
of such observers as Hall, Jameson, and Buckland, 
and which have afforded opportunities for splendid displays 
of the powers of Hutton, Werner, Playfaie, and 
CuviEii, have been not only useless, but even pernicious ? 
On visiting the districts enumerated above, my attention 
was forcibly arrested by the phenomena exhibited by the 
trap -rocks, and it is of these J now propose to lay a 
notice before the Society. But as these are considered by 
geologists as forming part of the same general series \\ ith 
those of Derbyshire, we shall first mention shortly the 
Derbyshire stratification. 
In the metalliferous strata of Derbyshire, it appears there 
are nine different alternations ; namely, grit-rock 120 yards, 
limestone-shale l60 yards, first hmestone-rock 50 yards, first 
toadstone or amygdaloid 20 yards, second limestone-rock 50 
yards, second toadstone or amygdaloid 30 yards, fourth lime- 
stone-rock 130 yards; making a total thickness of 650 yards. 
Here we perceive the beds of metalliferous limestone are se- 
parated by beds of trap rocks, called Toadstone. When a 
vein of lead is worked through the first limestone down to 
the toadstone, it ceases to contain ore, and often entirely 
disappears. On sinking through the toadstone to the second 
limestone, the ore is again found, but cut off by a lower 
