138 DAKTNS: GEOLOGY OF GRASSINGTON AND WENSLE Y DALE. 
sandy shales and thin poor sandstones. This change sets in imme- 
diately east of Crab Gill. It is quite possible that these degenerate 
representatives of the Lower Millstone Grits are, in Wensleydale, 
equivalent to the beds known as the "Ten Fathom Grits." If so, 
this will be an additional and very strong argument in favour of my 
view T , that the proper line to take as the base of the Millstone Grit 
is the top of the Little Limestone. 
The most important bed in Coverdale, above the Grassington 
Grits, is a thin but hard siliceous sandstone, like ganister. This 
rock forms a feature at the south-west end of Little Whernside. It 
is probably the same rock as that seen at Pinlow Pike south of Great 
Whernside. 
The next important rock is the Red Scar Grit. This bed retains 
its character of a coarse felspathic grit. It has also in Coverdale as 
in Wharfedale a coal associated with it. In Wharfedale the coal lies 
in the middle of the grit, which is a double rock. In Coverdale the 
coal lies near the top of the lower or felspathic part of the rock ; the 
upper part is a white siliceous ganister-like grit with rootlets, over 
which comes the tesselated limestone. It is remarkable how often 
limestones (generally thin) are connected with coals or seat-earths. 
The Limestone is overlaid by Shales containing a thin Sand- 
stone, and the Shales are succeeded by a Grit forming bold crags on 
Gateside Fell. It is overlaid by Shales and Sandstone, and these by 
a Grit forming another set of bold crags. This rock is a coarse Grit 
overlaid by white siliceous close-grained Sandstone, like Ganister, 
containing Stigmaria. Fragments of Sandstone containing shells 
are strewn about on the moor. These are doubtless fragments of 
the Shell-bed. The frequent occurrence of Ganister above the Red 
Scar Grit is important, and it is noteworthy that even as far south as 
Derbyshire beds of Ganister are apt to occur about this horizon, i.e., 
above the Kinder Scout Grit. In Coverdale these Ganisters become 
numerous and characteristic of the beds. It will be borne in mind 
that these beds all lie below the horizon of the so-called Third Grit 
of Lancashire or the Middle Grit of South Yorkshire. A section 
across Scrafton and Colsterdale Moors gives the following thickness 
of beds above the Red Scar Grit Coal : — 
