COLE : ON THE RED CHALK. 
33 
is the maximum thickness of the chalk at this highest range 
of elevation. 
In the third section, above Bishop Witton, the red chalk 
at its outer margin appears at a level of 475 ft. above the 
sea. A mile and a half farther east, in Deepdale, it crops 
out at 375 ft., the intervening hill rising to 675 ft., thus 
giving some 250 ft. for the extreme thickness of the white 
chalk at its highest elevation. 
In the fourth section, with the exception of the 100 ft. 
at the highest point, there is scarcely any white chalk at all, 
the red layers coming continually to the surface. 
At Huggate, five miles south of Burdale, distant five 
miles from the outer edge of the wolds, and twenty from 
Hornsea, at an elevation of 500 ft., about the sea level, the 
chalk is 339 ft. thick, as might be expected from the accom- 
panying section. (Section 5.) But a more interesting fact 
remains for notice, 
Two or three years ago I inspected a geological map of 
the wolds at the Jermyn Street Museum. The line of the 
red chalk was marked on the outer, i.e.., the northern and 
ivesteni sides of the wolds only. No one seemed to have any 
idea that the red chalk occurs on the inner or eastern side 
of the highest range. But it does undoubtedly at Burdale 
Station, where it may be seen at the bottom of the hill by 
the pond, exposed 6 or 7 ft. thick. The grey chalk appears 
also on the east side at Duggleby, the head of the great 
wold valley which runs to Bridlington, and also in a Slack, 
called Nova, some half-mile to the south, where there are 
springs. There is also every reason to suppose that it might 
be found in many parts of Thixendale valley, especially near 
Brownmoor. 
It seems then that the chalk of Yorkshire somewhat 
resembles a basin, or rather portion of a basin ; that the 
rim, which is now the thinnest portion, owing to subaerial 
3 
