of the Counties of Derry and Antrim. 211 
; : fO r ^ 
existence of powers of far superior energy to any we have 
ever known in action. 
Enumeration of some remarkable Inequalities in the Surface of 
our basaltic Area, produced since the Consolidation of its 
Strata. 
That we may better understand the facts I am proceeding 
to state, I shall assume (in the style of the mathematicians 
puta factum ) previous to demonstration, that the planes of our 
uniform, rectilineal strata, however interrupted we may now 
find them, were once continuous. 
Upon this supposition, the valley of the Mayola , between 
the stratified summits of Seafn and Slievegallon, is an excava- 
tion 1700 feet deep, and three miles wide, of which the whole 
materials have been completely carried off. 
To the northward of this excavation, between Seafn and 
Carntogher , the continuous accumulated strata of basalt are 
interrupted, and taken away quite down to the schistose sub- 
stratum ; while the untouched summits of the contiguous 
mountains, Carntogher, Seafn, and Monyneeny , are still strati- 
fied basalt. 
On the eastern side of our area, immediately to the south- 
ward of Kello and Connor, a similar operation has been per- 
formed, attended by still more extraordinary circumstances. 
We here find a district near four miles in diameter, called 
the Sandy Braes ; over this whole space the basaltic stratifica- 
tion has been carried off, and the operation has reached deep 
into a very singular substratum ; a reddish breccia, by some 
E e 2 
