in Yorkshire and Durham. 25 
allow me to ascertain the exact relation which the trap on that 
side of the water has to the contiguous strata. Above Egglestone 
bank another mass of trap, to all appearance immediately con- 
nected with that which has been described, crosses the road about 
a mile to the north-west of the village. It there assumes the 
unequivocal characters of a dyke, ranges (as nearly as I could 
discover from very imperfect data) E. by N. and a few hun- 
dred yards above the road crosses the western branch of the 
rivulet which runs past Egglestone. A quarter of a mile farther 
up the same branch of the rivulet, a second dyke crosses its bed 
and seems to range about S. E. by 8. From what has been stated 
it appears probable that these two dykes unite, or intersect each 
other. Their concourse will probably be found on the moor 
above the new smelting-house. The former, where it is seen 
above Egglestone, is about forty feet wide, and cuts through a 
bed of coarse grit, provincially called firestone. The latter is 
about sixty feet wide, and is associated with gritstone and a band 
of indurated shale which has been much quarried for whetstones. 
It would certainly be very interesting to trace these dykes 
as far as possible through the eastern moors, as there can be 
little doubt of their connexion with some of those masses of trap 
which traverse the great coal-field. My own observations were 
much too limited to complete this task. I however found on 
Woolly Hills, in the Woodland Fells, several quarries opened in 
a dyke which, from its position as well as in its structure, seemed 
to form a connecting link between the trap of High Teesdale 
and some of the dykes which traverse the country near Cockfield 
Fell*. 
* It is stated by Mr. Winch (Geological Transactions, vol, IV. p- 76.) That « at 
Egglestone, three miles below Middleton, a very strong vein of basalt may be seen crossing 
the Tees in a diagonal direction.” | suspect that he here alludes to the mass of basalt above. 
mentioned, which appears on the left bank of the Tees opposite to the entrance of the Lune, 
Vol. UL. Part I. D as 
