316 [Proc. B.N.F.C, 



found in bogs, marshes, or by the sea-shore. Various species of 

 Heaths are often dominant plants on peat. Under the Heather 

 there is again a second stratum of smaller plants, associated with 

 it. Again, bog-pools and drains have their special associations, 

 Utria/laria, Riccia, &c, and various species of Mosses and 

 Lichens are found in great abundance on peat. 



" THE CHALCEDONY OF BALLYBOLAND, CO. ANTRIM." 



The monthly meeting of the Geological Section of the Club 

 was held in the Museum on 23rd March, Mr. H. L. Orr 

 presiding. 



An interesting communication on " The Chalcedony of 

 Ballyboland. Co. Antrim," was brought before the meeting by 

 Mr. James Strachan. The lecturer introduced the subject by 

 stating that acid substances such as chalcedony, which was nearly 

 pure silica, were not very common in the basalts of Co. Antrim. 

 The chalcedony of Ballyboland, found in the large quarry close to 

 the railway, mid-way between Dunloy and Ballymoney, presented 

 some interesting features when considered geogenetically. The 

 basalt of Ballyboland was found to be intermediate in structure 

 between a basalt and a dolerite, and might be regarded either as 

 a fairly coarse-grained basalt or a very fine-grained dolerite. In 

 composition it was typically basic, consisting of a plagioclase 

 felspar, augite, olivine, and magnetite. The felspar shewed 

 fiuxional tendencies and enwrapped the augite grains, while the 

 olivines were large porphyritic crystals, with typical inclusions of 

 magnetite and chlorite. Chlorite was also an interstitial mineral. 

 The rock had a greenish-blue colour, but here and there it passed 

 into irregularly shaped lenticular masses and streaks of a purple or 

 puce-colour. In this puce-coloured rock the most of the 

 chalcedony was found in long thin veins or cracks, varying in 

 thickness from .5 to 5 cms., but having an average thickness of 

 about 1 to 1.5 cms. 



