634 



[Proc. B.N.F.C 



The following were elected members of the Club : — Miss 

 M. K. Duffin, Miss F. M. Ritchie, Miss I. Doherty, Miss N. 

 Humphreys, Miss S. Bell, Miss I. Boyd, and Miss E. C. 

 Montgomery. 



"OUTLINE OF GEOLOGICAL OBSERVATIONS IN 

 NORTH-EAST LONDONDERRY COLLECTED DURING 



THE PROGRESS OF REVISION WORK." 



At the fifth meeting of the Winter Session on 18th March, 

 the above paper was read by Dr. A. R. Dwerryhouse on behalf of 

 the author, Mr. J. R. Kilroe, A.R.C.Sc.L, who was unable to be 

 present at the meeting. Mr. Robert J. Welch, M.R.I. A., occupied 

 the chair, and there was a large attendance of the members of the 

 Geological Section of the Club. 



PHYSICAL GEOLOGY. 



" Many features of importance in this highly interesting region 

 do not seem to have received much attention in the original rapid 

 survey on the one-inch scale. It is, therefore,' here proposed to 

 give an outline of the principal conclusions to which I have been 

 led, in the revised survey of the region on the six-inch scale, 

 particularly North-east Londonderry ; and this is offered with the 

 sanction of the Director of the Geological Survey. Many details 

 are reserved for the more extended account. 



The watershed separating the valleys of the Roe and Bann 

 passes at or near to the summits of the escarpment overlooking 

 the former river, being only about 4^2 to 5^ miles distant from 

 it ; while the watershed is 6 to 9 miles distant from the Bann. 



One extremely interesting fact connected with the formation 

 of the Roe Valley is, that the principal features of the escarpment 

 — Benevenagh, Keady Hill, Donald's Hill, and Benbradagh — have 

 receded eastward from the course of the Roe, approximately in 

 inverse proportion to their heights. This we might expect on the 

 hypothesis that the valley and escarpment alike owe their origin 



