76 
FIRST REPORT— 1831 . 
Mr. Wm. Hutton read a paper upon the Whin Sill of 
Cumberland and Northumberland. 
A bed of Stratiform Basalt is well known to occur exten¬ 
sively in connexion with the Mountain Limestone Rocks of 
the North of England, and is called in Alston Moor and the 
adjoining mining districts, “the Whin Sill.” This bed has 
naturally a good deal of geological interest attached to it, from 
the circumstance that rocks of its class are generally found 
under conditions which indicate that their production is entirely 
independent both as to antiquity and origin of that of the 
Strata which they divide,—and upon which, at the points of 
contact, they have produced mechanical and chemical changes 
which afford the most conclusive evidence of their violent in¬ 
trusion since the deposition and consolidation of those Strata. 
The Whin Sill is visible in many of the streams running into 
the South Tyne from the West, and may be seen in the bed 
of the Tyne itself at Tyne-liead. It occurs in the bed of the 
Wear, in Teesdale, where it is extensively developed, and in 
the Lime ; in short, throughout the whole district wherever the 
water-courses, or the operations of the miner, pierce deep 
enough : its basset-edge may also be traced almost uninter¬ 
ruptedly from Helton in Westmoreland to TindaleFell in Nor¬ 
thumberland.—Here the whole carboniferous formation is broken 
through by the “ great Stublick Dyke,” which throws down the 
Whin Sill along with the other beds of the formation to an 
immense depth; its edge reappears on the north side of this dyke 
at Wall Town Crags, near Glenwhelt, in Northumberland, rising 
rapidly to the North, and from this spot it can be traced almost 
throughout the county of Northumberland to the sea-coast near 
Newton; it occurs again with other beds of the carboniferous 
formation in consequence of a general depression of the strata 
a little south of Bamborough, from whence it sweeps round by 
Belford to Kyloe on the coast, near to which place it finally dis¬ 
appears. 
In the course of this bed northward from Alston Moor, it ap¬ 
pears to rise in the series of strata, from ‘ the putting in of new 
beds, as the miners term it; and of course it is found in contact 
with all the varieties of rock composing the carboniferous for¬ 
mation. It is generally in one bed, sometimes in two, and once 
at least it occurs in three beds. 
The action of heat in hardening the rocks near it and ren¬ 
dering the limestone crystalline, can generally be observed ac¬ 
companying this bed, but nowhere to such an extent as in High 
Teesdale. 
After an attentive examination of the appearances exhibited 
