48 
whole of the phenomena connected with slaty cleavage point to the 
conclusion that the highly cleaved beds were in a more plastic 
condition than the overlying and underlying strata when the lateral 
pressure which caused the cleavage was applied to them, and that 
those portions of the cleaved beds where cleavage occurs in its 
greatest intensity had yielded sufficiently to the pressure, while the 
remainder had only yielded partially. 
There are two beds at the base, and seven or eight beds near 
the top of the volcanic series, in which there is more or less slaty 
cleavage, but in all the middle portion of the series, with the 
exception of one place, near Eagle Crag, in Borrowdale, it appears 
to be altogether absent. The beds at the base have been, and are 
now being, worked in Borrowdale and near Buttermere; and those 
near the top of the series, at Walna Scar, Coniston, Tilberthwaite, 
Elterwater, Langdale, Rydal, Grasmere, Kentmere, and Cawdale 
Moor. The Borrowdale and Buttermere quarries yield about three 
thousand five hundred tons of slate per annum, and give employ- 
ment to about one hundred and twenty men; and the Westmorland 
and Lancashire quarries yield about four thousand tons per annum, 
and give employment to about two hundred men, thus constituting 
one of the most important industries in the Lake Country. The 
slate obtained from these quarries is unrivalled for beauty, strength, 
and durability. In the two latter qualities it is greatly superior to 
Welsh sedimentary slate, but it has the disadvantage of being 
slightly heavier; the best quality of green slate yields four slates 
to the inch, and one ton will cover about thirty-two square yards 
of roof. 
The two beds of fine cleaved ash, called locally, “slate metal,” 
which occur at the base of the volcanic series, lie parallel to the 
great fault which separates that series from the Skiddaw Slates, the 
strike of the beds agreeing to a considerable extent with the strike 
of the fault, the lower bed being about one thousand or one thou- 
sand one hundred feet from it. The general dip of the slate metal 
also coincides with that of the fault, and of the underlying and over- 
lying beds, being about thirty degrees towards the south-east; the 
direction of the cleavage planes is nearly vertical. The beds of 
