92 Mr. Mills’s Obfervations on 
of the hollows between the hills met with beds of ftones, 
fimilar to thofe I had feen on the beach. Approaching the 
weftern ftiore, Ifaw a cavern, whofe mouth opened to the eaft- 
ward, and whofe bottom was covered with water. Pafting 
this, I arrived at a narrow fteep path, which leads down the 
cliffs to the fhore. Here are feveral caverns, whofe general 
range is S.E. into the cliffs, which are compofed of chert. 
South from thefe caverns, in travelling the fandy fhore, I paffed 
a vein of laminated hornftone (approaching to the nature of 
a fhiftus) containing pyrites in the joints of the ftone, which 
range nearly N.N.W. and S.S.E. Farther fouth is an immenfe 
Whyn Dyke, burfting from the cliffs; it {lands vertically, is 
many yards in heighth, projects from the cliffs to the north- 
weft ward, and in that direction runs many fathoms into the 
fea. It bears the buffeting of the waves of the Atlantic Ocean 
from the fouth- weft, and feems to defy their rage, though its 
breadth, compared with its height and length, is very incon- 
siderable, it not being more than five or fix yards wide. It is of 
a dark granular fubftance, very fimilar to the Whyn Dyke 
near Freeport, excepting that the central part is fofter and of 
a paler colour. The outer fides, which are each about two 
feet thick, are of a very dark colour, hard, contain fome blad- 
der-holes and fpecks of zeolite, are detached from the center 
(in general) by very fmall joints, and the whole is divided by 
tran fverfe joints into irregular polygons of various dimen fions. 
If this ftupendous objedt is viewed from the north, it has 
much the appearance of a lofty wall of human fabrication. 
A fmall diftance more to the fouthward is the great cave, in 
the Erfe dialed!: called Ea mawr. The entrance is near twenty- 
three yards wide, and from fix to eight yards high. After 
going in a little way the roof rifes, and the cavern extends in 
4 breadth ; 
