initio, j cj77 



an intrusive sill of fairly coarse holocrystalline olivine dolerite, 

 found by Mr. Strachan to be identical in petrographical character 

 with the dolerite of Ballygalley Head, about ten miles eastward ; 

 the other intrusion, N.E. of Crag Hill, is a small boss of dolerite, 

 so finely grained that it may be called a true aphanite. On its 

 summit two marked sets of glacial striae were observed, running 

 respectively nearly North and South and East and West. At 

 Ballymurphy fine specimens of selenite and some pseudomorphs — 

 after crystals of rock salt — were found in the Trias. Ailsa Craig 

 riebeckite rock and other " erratics " were noted in the 

 fioulder-Clav. 



Microscopic exhibits and demonstrations by members of the 

 Section were given on 30th November, the opening meeting of the 

 Geological Winter Session. On 29th January Mr. James Strachan 

 gave an instructive lecture on " The Count)- Antrim Basaltic 

 l'lateau." After describing its main features, Mr. Strachan 

 proceeded to give a petrological classification of the various types 

 of basaltic rock found in the county. The zeolite-bearing lavas 

 were described, and the origin of these interesting minerals 

 discussed. In describing the interbasaltic beds, the lecturer 

 referred to the recent view that the iron ores and bauxite had 

 largely originated from the weathering of basalt in situ, but he 

 ventured to dispute this theory as applied to at least the upper- 

 most series of the interbasaltic beds, which undoubtedly showed 

 strati graphical evidence of sedimentation. Mr. Strachan concluded 

 his lecture with a brief reference to the effects of glacial action in 

 carving out the scenery of the county. Another lecture to have 

 been given by Mr. J. R. Kilroe, A.R.C.Sc.L, was transferred, by- 

 request, to a later meeting of the whole Club. 



In Glacial Geology the Committee report considerable 

 progress, especially in the critical region west of the Bann. The 

 area of distribution of Ailsa Craig rock has been extended beyond 

 the Roe. Madame Christen having detected it at Moys, about two 

 miles west of that river, and at an elevation considerably above 



