High Tees- 
dale. 
Denudation. 
144 Professor S—EpGwick on the 
Secrion II. 
On the Structure of High Teesdale. 
Tue descriptions given in the preceding Section, are suffi- 
ciently general to be applied to the whole system of the vallies 
which traverse the eastern flank of the great calcareous chain 
of the north of England. I shall now direct my attention, 
almost exclusively, to the phenomena which are exhibited in 
High Teesdale. As a matter of convenience, this part of the 
valley will be supposed to commence near the village of Eglestone. 
For above that place the dale begins to assume an austere aspect, 
which differs greatly from the softer and more picturesque fea- 
tures of the lower banks of the river. There also commences 
a series of phenomena to which I wish principally to direct the 
attention of the Society. 
That High Teesdale has been formed by denudation, is 
proved unequivocally, by the whole contour of the valley, by 
the ramifications of the tributary streams, and by the accumu- 
lations of diluvial matter, in almost every place, where it was 
possible for it to find a lodgement*. This assertion is, however, 
by no means intended to exclude the supposition of pre-existing 
inequalities and fractures, which may have enabled the diluvian 
torrents to pass in one direction rather than another. But facts 
of this kind are, for the most part, too much removed from 
direct observation to be deserying of much attention. 
* A person, practised in observations of this kind, would, from the mere external 
form of the country, generally succeed in pointing out the places where diluvial-gravel 
has been much accumulated. Transported materials, containing large blocks of trap, 
limestone and sandstone, are in great abundance near the junction of the Lune and the 
Tees. On the right bank of the Tees, between Lonton and Eglestone, the gravel is in 
some places not less than a hundred feet thick; but it gradually becomes comminuted, 
and in some places passes into a coarse sand, 
