DYKES, MINERAL VEINS, 8tc. 81 
raised up, and their free ends immersed in the lower parts of the 
Whin sill. 
Widdyhank . — The anomalous breccia above described, and the uncon- 
formity of the Whin sill to the subjacent beds, are the principal facts 
here observable. 
White Force.— At this fine waterfall the thick Whin sill rests in 
one part on granular limestone, thirty feet thick, and in another on 
two beds of limestone separated by a thin bed of indurated shale. 
Portions of the upper members, limestone and shale, are raised up and 
enveloped in the Whin, which penetrates in two wedge-shaped expan- 
sions between the limestones and shale. 
High Force . — In the new road from Brigghouse Inn to the water- 
fall a small section was made through a point of the Whin sill, about 
fifty yards below the High force, and an interesting fact was dis- 
closed. At the High force itself not the least trace of mechanical 
force has been observed at the junction of the trap and shale ; but 
here a limited mass of gray sandstone rock, lying below the Whin, 
has been partially entangled in it, as the Diagram, No. 11 will shew 
better than any description. Near the junction surfaces, both the 
Whin and the sandstone are greatly altered ; the former is ochraceous 
and softened, the latter calcined to whiteness, and singularly fis- 
sured. In all these cases the mechanical movements are confined to 
the beds below the Whin. 
From near the eastern end of the escarpment of the Whin sill 
in Teesdale, arise two or three great basaltic dykes, which have been 
examined by Professor Sedgwick, and possess a high interest in coal- 
working and theoretical geology. The Whin sill, being about a 
quarter of a mile from the river Tees on the south side, ceases to 
be visible at about half a mile from the junction of this river with 
the water of Lunedale. At this junction one of the Whin dykes 
is supposed to cross the valley pointing towards the apparent termi- 
M 
