186 
HUGHES : INGLEBOROUGH. 
On the whole, therefore, the general consideration of the 
place of this plain, and the close examination of each section 
in it, supports the view that, as it stands, it is a sea plain, and 
that the fragments on it are water-w^orn and water-borne, though 
this is not inconsistent with the supposition that there may- 
have been glaciers on the adjoining mountains if there were 
any high enough to give rise to them. 
In the diagram (Fig. 4) I have indicated, by the line 
A B C D, what I conceive to have been the character of the 
surface at one stage of the pre-Carboniferous denudations. 
DIAGRAM ILLCSTRATIXG RELATION OF BASEMENT BED OF CARBONIFEROUS 
TO THE DEVONIAN. 
Fig. 4. 
A B C D. The thick line represents the pre-Carboniferous surface. 
E E. Sinkin}> mountain land on margin of Carboniferous sea. 
F F. Bottoms of valleys in the part of that sinking mountain land, which, before 
being planed off, had been submerged below sea level and thus protected 
from further waste. 
a. Carboniferous. (Passage.) 
b. Devonian, or Upper Old Red, or Basement Bed of Carboniferous. (Great 
unconformity.) 
c. Merthynian, or Lower Old Red, of Carmarthenshire and Herefordshire. 
(Passage.) 
d. Silurian and Bala. 
At the right-hand end of the section were mountains, E E, 
which fed the valleys F F, such as that which we see now full 
of red conglomerate at the foot of UUswater, or that which 
runs by Sedbergh, Barbon, and Earby Lonsdale.* 
The sea arrested sub-aerial denudation and planed off 
what remained of the land from B to C, that is over the area 
on which Ingleborough now stands. It may have removed 
the mountains E E also, as it removed the similar mountains 
which once existed on either side of F and F. But at the left- 
hand end of the diagram the land was being depressed earlier 
* Mem. Geol. Survey, 98. S.E.. p. lo ; 98, N.E., p. 14. 
