Caldron Snout, 
&e. 
162 Professor Sepewick on the 
as I have before remarked, is synonymous with the word stratum, 
and the Whin-Sill is theoretically assumed (in the general sec- 
tion, No, 71.) to be parallel to the upper and lower beds of the 
great formation of mountain-limestone. 
There are some other sections which confirm, in the strongest 
manner, the conclusion I am endeavouring to establish. But 
they are so intimately connected with the changes produced in 
the other beds, by the contact of the trap, that they will be 
better described in another part of this Paper. 
At Caldron Snout, the waters of the Tees are once more 
precipitated over the escarpment of the trap, not as at High 
Force, in one perpendicular descent, but in a rapid succession 
of cascades, which together form a scene of great magnificence. 
We may ascend, without difficulty, among the broken prismatic 
blocks, which are strown about the edge of the cataract, and 
soon after we reach the upper surface of the trap, the river is 
found to expand into a deep and nearly stagnant pool of water, 
called the Weel. Beyond this place it branches out into several 
torrents, which form the drainage of one side of Cross Fell. 
Not many hundred yards to the east of the Weel, a bed of gra- 
nular limestone, and a bed of whetstone-slate, are seen to rest 
on a very irregular surface of trap: and still farther up the hill, 
we find the regular parallel beds belonging to the higher parts 
of the formation of metalliferous limestone. Nl 
The trap may be also followed up the denudation of Birk- 
dale, where it is surmounted by a bed of granular limestone, in 
external character, exactly like that which was last-mentioned. 
It was not, however, my object to trace the range of the trap 
in that direction, or to ascertain its probable connexion with the 
rocks of the same formation which appear on the west side of 
the Cross Fell chain. 
The preceding description, with the accompanying sections, 
