62 
description of the rocks 
and to Flashy, will render the result of this complicated investigation 
somewhat clearer. (See JDiag. No. 10.) 
To these two shale series thus distinguished, I give the name of 
Nidderdale (upper) and Bolland (lower) shale. The latter is seen 
exclusively in all the west of Craven, the former exclusively in Nid- 
derdale ; both of them occur in the south-east of Craven, in the vales 
of Todmorden, and constitute the general slialy mass along the summit 
of Drainage, partly associated with, but principally lying beneath the 
millstone grit of Derbyshire. 
The following is a general view of the groups of the millstone grit 
and shale series in the Wharfedale district. 
Upper group Brimham grit 
{ Flagstone and plate group 
Sandgill grit 
Alternating plates, grits, and coal 
Lower group { Ingleborough grit and coal ... 
I Chert series 
Main limestone. 
\ 
It remains to be determined how to apply this general table to the 
variable mass of sandstones, shales, and coal, with thin limestones, which 
occupy the high summits between the northern dales. 
Commencing at Greenhow hill we have the following section in 
general terms, derived from the observations of Mr. Nathan Newbold, in 
Cock hill level, combined with my own investigations. 
Upper grit group _ 
$ °f Rrimham, Guisecliff, Poxstones, and ? 
100 to 360 
'■ the Wharfedale crags ... 3 
Feet » 
Upper plate group J 
186+ j 
f Flaggy grit called ‘top grit’ ... 
Ellenscare plate, with laminar chert,? 
coal, and flagstone ... 5 
36 
150 
Middle grit 
Sandgill grit (coarse grit) 
48 
i 
Feet. 
150 or more. 
250 estimated. 
48 at Greenhow. 
345 at Greenhow. 
100 to 300. 
