440 
TIIH OKriLf)C;[ST. 
liiiipstono, diyidod hy thin layers of saudstouo and "plates," and one bed of 
coal, _ wiiicli is not continuous. Tiic upper limestone — under the names of 
Camfeli-, Main-, Parkhead-, and Twelvc-fatiiom-limestone — is one of the most 
constant iu tlic dist.riet. The s^Tcafest thickness of this grou|) is . 200 feet. 
( h) A group of llagslones, called the " IIa\^•cs-^lagstoiles," from their great 
development at the head of Wenslevdale ; it contains one strong band of 
limestone, and a great Ihickuess of gritstones and "plates," very varied in their 
character. Tin- thickness of these 'flagstones is 500 to 600 feet. 
(c) The "Black-limestone" group containing two well marked beds of 
limestones, the lower cmc of which produces the grey encrinital marble of 
Dent, with " plates" and grits. Its thickness is ... . 200 to 300 feet. 
3rd. J?elow this is the lower " Scar-limestone," of a much more homo- 
genous character, the thickness of which, as it forms the bottom-rock of 
most of 1 he valleys, has not been accurately measured. It camiot, however, 
be less than ' 500 feet. 
The general dip of this series is south-cast, and in following the beds in that 
direction to their disappearance nuder the magnesian limestone and New Red 
sandstone, the tliickness of groups a, h, and c becomes gradually less by the 
obliteration of the two lower series first; and finally by the thinning out and 
complete disappearance of the upper one, until in Wharfedale and Nidderdale 
the Millstone-grit reposes directly upon the lower " Scar-limestone," which 
has increased in thickness until, from being the bottom-rock of Wenslcydale, 
it alnu)st reaches the top of Great AVhernside, and forms the sides of the deep 
valley of the Wharfe. 
But another cause has been at work to alter the face of the country besides 
the gradual change in the thickness of the beds. On a cm-ve, drawn from 
Settle to Harrogate, at the foot of the dales that fall to the south from the 
chain of liills skirting the southern side of Wenslcydale, the lower "Scar- 
limestone" appears to abut against, instead of underlying, the Millstone-grit. 
This is caused by a downthrow of the latter, on the line called the " Craven- 
fault," which beginning near Kirkby Londsdalc, where the limestone and the 
Cauibrian slates have their relations much altered, may be followed towards 
the east, in which direction it breaks up the limestone itself, as in the district 
of Craven, and still further east disturbs the position of the limestone and the 
Millstone-grit, until at Grecnliow-hill the last traces of it are exposed before it 
disappears under the Magncsian-limestone, which being a later formation has 
covered \ip all tokens of the disturbance. 
Whenever the streams run through the upper " Scar-Iunestones" their 
general course is eastwardly, with a slight tendency to curve to the south ; but 
as soon as these beds disapjjear, and the lower " Scar-limestone" comes upper- 
most, we find that the valleys turn southward until they reach the line of the 
Craven-fault, when they follow again the natural dip of the beds. This fault 
thus becomes the cause of much of the variety in the character of the 
scenery of these Yorkshire dales. 
Our road lay out of Weusleydale, up one of its lateral valleys called Bishop- 
dale, and over Kidstone's Pass, a route practicable for carriages, which can l)e 
said neither of the pass to the right out of Baydale, over Stake Pell, nor 
of that to the left out of Coverdale, over Buckdeu Pike, although both are 
sometimes attempted. 
All the valleys out of Wenslcydale are either destitute of roads leading 
southward, or the passes are excessively steep on their southern faces. This 
fact is connected with another in the physical geography of the district ; viz., 
that Wenslcydale is bounded to the north by an unbroken chain of hills, while 
on the south five large valleys run into it. Swalcdale and Teesdale are 
equally destitute of direct lateral valleys from cither the south or north. 
