C. T. Clough—The Whin Sill of Teesdale. 435 
with saccharoid limestone below. The section is rudely represented 
in Fig. 1.1. The Whin is seen cutting diagonally down through two 
posts of nearly horizontal limestone: the top post is first of all cut 
completely through, and then the next is cut partially through. 
The limestone has not assumed a dip parallel to the inclined Whin 
base. 
On the top of Cronkley Fell, in Yorkshire, the beds above the 
Whin are lying almost horizontally, and are as follows, beginning 
from below :— 
a. Limestone, 38ft.? 
6. Sandstone, fine grained, massive or flagey, 40ft. 
e. Limestone, 6ft. 
d. Sandstone, 42ft. 
In some places all these beds in their full thickness can be seen 
resting on the Whin. In other closely adjoining places we find the 
Whin has risen up almost vertically through the lower beds, a, b, 
and ¢. The sketch (Fig. 2) shows the Whin rising up near the 
limestone a. The locality which is sketched shows very clearly that 
the posts of limestone near the Whin are quite undisturbed—there 
has been no tendency for the Whin to lift them up with itself as it 
Fic. 2. Basalt and saccharoid Limstone, ‘‘ cheek by jowl,’’ White Well, 
Cronkley Fell. 
a Basalt, heather-covered. 6 Limestone, grass-covered 
rises. That we get such oppositions of inclined Whin faces and 
edges of horizontal sedimentary beds cannot be accounted for by 
faults: in the first place we should frequently have to imagine 
faults almost circular, in the second we can sometimes see clearly 
that, when the Whin rises, it has resting on it higher beds than it 
had when it was on a lower level, a thickness of beds corresponding 
to the height of its rise being missing; in the third the Whin faces 
can usually be made out to be not fault faces, but original surfaces 
exposed by denudation.® 
1 This section is noticed and figured by Sedgwick in the paper already alluded to : 
he notices it as being specially interesting because :—1. The Whin is not parallel to the 
beds on which it rests. 2. The limestone has been altered into a saccharoid condition 
by the Whin. To these we may add: 3. Of the occurrence of Garnets, Prehnite, 
and Rutile (?) in the Whin, near its surface. 4. Of showing very well the bending 
round of the master joints in the Whin, as its base changes from a horizontal to an 
inclined position ; the joints always keeping perpendicular to the base of the Whin. 
2 The limestone a is probably the top of the Melmerby Scar Limestone. : 
8 That these surfaces are original is made out by—1. The extremely fine grain of 
the Whin. 2. The occurrence of Garnets and Pyrites, on or near them. 3. The 
presence of bits of altered rock clinging to them in places. 
