478 ON THE TRA1MK)CKS IN YORKSHIRE, &C. 
solid ore of foui' inches, which intersects the trap. 
The specimens I have now the honour of laying before the 
Society, are from a vein which runs east and west in the 
basalt, which extends over this district immediately at the 
foot of Crossfell, and is at present working at the point 
where Troutbeck, coming from the south-west, joins the 
river Tees. The vein from which I obtained these speci- 
mens is supposed to be a prolongation of one at present 
working in Harwood, If this could be ascertained, I 
think it might lead to some very interesting speculations 
on the subject. My friend Mr Jobling of Newtonhall, 
to whose kindness I am indebted for much useful infor- 
mation, is not aware there are at present any veins raising 
ore in this district, but there are many old workings in 
the basalt. 
The trap rises to a considerable elevation, and in prodi- 
gious masses, from the High force to the south of Croakley 
and Croakley Fell, and at Cauldron Snout, about six miles 
NW. from the Highforce, where it again interrupts the pro- 
gress of the Tees, and gives rise to a succession of beautiful 
cascades, to the height of 200 feet. Here it rests on the same 
limestone, and is covered to the NE. by a white and highly 
crystalline quartz-rock, which is intersected in every direc- 
tion by bearing lead-veins, which the miners say penetrate 
the trap, but, owing to the hardness of the substance, has 
not been profitable to work. The colour of the trap (of 
which you have here a specimen) is bluish-grey, a mixture 
of augite and white felspar in small crystals. It is extreme- 
ly hard and tough, and the fracture inclined to conchoidal. 
It sometimes inclines to the columnar form, particularly at the 
Highforce, and other interesting sections in the neighbour- 
hood. The dip of the trap corresponds with that of the 
other strata NE. The most intelligent miners are of opi- 
nion tliat this rock may be traced for above thirty miles to 
