08 Mr. TreveltuIn's Notice of a Bed of Whin. 



No. X. — Notice of a Bed of Wsm, at Stanhope, in Weardale. By 

 W. C. Trevelyan, Esq., of Wallington. 



Read ApeilSO, 1830. 



The bed of Whin which occurs in the Lead Measures at Stanhope, in 

 Weardale, appearing to be unnoticed except by Westgarth Foester, 

 in page 112 of his Section of the Strata, ^c. 2d edition, where he has mis- 

 taken it for the great Whin-sill, which is much lower in the series (No. 

 192 of his Section') ; a short notice of it may, perhaps, be interesting. 



This bed is first met with near Unthank Bridge, at the west end of 

 Stanhope, where it forms, for some hundred yards, the bed of the river 

 Wear, and rises on its banks in low picturesque columnar rocks. The 

 thickness of it cannot here be ascertained, but, about half a mile to the 

 west, in a burn, which, I think, is called Allergill, which runs into the 

 Wear from the south, a good section is exposed, forming a picturesque 

 waterfall, where it appears to be about 20 feet thick, and is superincum- 

 bent on a Limestone containing Pyrites, resembling that which occurs 

 in the section in Rookhope Burn : from hence it may, I think, be traced 

 by examining the beds of the burns as far west as Westenhope ; and, 

 on the north side of the Wear, it may also be followed almost continu- 

 ously to Rookhope Burn, near Hole House, about three quarters of a 

 mile above its junction with the Wear (where the section represented in 

 the sketch occurs), it there is only 7 feet thick ; from this decrease in its 

 thickness, and from not having been able to trace it any further west, 

 I am inclined to think that it is only of partial extent, as, indeed, sup- 

 posing Whin to be of volcanic origin, and ejected from below (in favour 

 of which theory there are many proofs), might naturally be expected. 



This rock appears to occur in the fourth, or three-yard Lime (No. 16S 



