MOETIMER: OEIGIN OF CHALK DALES. 
39 
been deposited upon a hill of lias clay. The red chalk is seen at 
the corner of the v&Wej just south, so the fault would not be a large 
one. The fault also would have to wind about a g-ood deal, and I 
do not like winding- faults." In reply to this it seems improbable 
that a yielding substance as lias clay should present such an irregular 
surface at the time of the deposition of the chalk, as to account for 
the different elevations of the base of the chalk in the valley bottoms. 
And if we admit this for the lias clays, we must also admit it for 
the Kimmeridge and the Neocomian clays, which are moi e frequently 
found to differ very considerably in elevation, in very short, 
distances, between one side and the other side of a valley. The 
irreg-ularity of the base of the chalk, in Wold Dale, as sometimes 
in others, and the apparently crooked appearance of the dale, or fault, 
may be partly due to the masses of chalk having slipped from the 
upthrow or western side of the valley, to lower levels, and so masked 
the true base of the chalk, which on the upthrow side is often higher 
than it seems, besides, a small fault might as easily be crooked as 
straight. 
In further support of my theory of the great strain and dis- 
placement the cretaceous beds of Yorkshire have sustained, I wish to 
mention the fact, though the general dip of the whole mass is to the 
E. and S.E., scarcely any two adjoining pits show the same degree, or 
direction of dip. Local variations in the disturbed beds are numerous 
and frequently great. Crumpling of the strata is also frequent. 
In the Bempton cliffs, a little north of Flamborough, there is a grand 
example of the crumpling of beds, extending from top to bottom of 
the cliff, a distance of about 300 ft., with a slight variation at the 
bottom. At Foxholes, Weaverthorpe, Langtoft, Whinmoor Build, 
Heslerton Brow, and in two places in the railway cutting between 
Marton and Hunmanby Stations, are similar extensive crumplings 
and displacements of the chalk strata, in some places attended with 
slight faulting. Many minor crumplings may also be observed 
throughout the area. Though these crumplings are most likely due 
to a period of subsidence, acting on lines in a certain dii ection ; while 
the valleys were formed during a period of upheaval acting along 
lines in a different direction ; they clearly indicate extensive terrestrial 
