28 
BLAKE : EAST YORKSHIRE. 
that the Howardian hills, so often disturbed and dislocated, 
could hold together no longer, but opened that remarkable 
gap by which the water which drains off the moorlands, collect- 
ing in the vale of Pickering, is carried off by the Derwent to 
the south. It might perhaps be thought by some that we have 
here another example, like that of the Weald, of the 
transverse valleys having been worn out when the centre 
was at a higher elevation than the surrounding country. 
This, however, with the highest formation in the centre, 
and that let down by Faults, is here impossible. The line of 
the valley south of Malton probably is also a Fault, or due 
to several. The way in which the inliers of Bransdale, 
Farndale, and Rosedale have been formed is probably this. 
The water originally flowing over the natural slope of the 
country, would find sandstones on the high ground, but on 
nearing the vale of Pickering, would eat into the calcareous 
rocks with greater rapidity, thus producing the mouths of 
the valleys, and adding force to the fall of the water above 
by shortening its length of flow to the lower level ; so it 
would at length work its way downwards, till, when it 
reached the Lias, the yielding shales would soon enable 
it to scoop out a wider valley. In the northern valleys the 
capping of Inferior Oolite is so thin that it is only due to 
undulations and Faults in the strata, which here and there 
bring the upper beds down into the way of the stream, that 
the whole of them is not one long valley simply worn down 
into the Lias, and having its embouchure at Whitby. 
The effect of the glacial epoch on East Yorkshire is fairly 
well marked. The rocks, indeed, are not of a character that 
would preserve any glacial striao, and none to my knowledge 
have ever been found. The rounded surface, however, of 
some portions of the basaltic dyke almost call a roche moutonnie 
to mind. The larger number of effects, however, are those 
produced while the land was submerged. In the northern 
