of the Counties' of Derry and Antrim. 237 
composed the projecting parts of our northern facades, and 
precipices, had totally disappeared. 
The removed parts of the limestone stratum on the west 
side of our area have shared the same fate, for where the 
chain of mountains extending from Magilligan Rock to Bien- 
braddock, is interrupted by vallies at Stradreagh, Drumrommer , 
and Ballyness, it is obvious that the limestone stratum was 
once continuous to the high points where it shews itself on 
Keady, and the mountains on each side ; its thickness too, 
wherever we can try it, is very great ; yet this stratum, which 
in its entire state must have spread like a roof far above the 
present surface of these valleys ( which are now sunk deep 
into the schistose substratum) has not left a particle of its 
debris behind, nor is a single lump of white limestone to be 
found, until we come to the quarries, that is, to the edge of the 
solid, untouched stratum. 
Conclusions. 
The conclusions that unavoidably follow, from the consi- 
deration of these facts are, 
That the hills and mountains, in the district I have been 
describing, were not raised up or formed as they now stand, 
but that they are the undisturbed remains of strata that were 
left behind, when stupendous operations carried away the 
parts that were once contiguous to them. 
That the inequalities of this surface were all produced by 
causes acting from above, and carrying off' whatever they 
touched, without in the least disturbing what was left behind. 
F f 
MDCCCVIII. 
