12 [Proc. B N. F. C, 



a small cliff section, and here are exposed several of the dykes 

 which cut through the strata every hundred yards or so along 

 this part of the beach. The effect of such masses of molten 

 rock as filled up these fissures, either from volcanic overflows or 

 from being pushed upwards by subterranean forces, was such as 

 to alter the adjacent friable sandstone into compact crystalline 

 rock, and in many cases to bend the strata in a remarkable 

 manner. Judging from the fact that these dykes vary in their 

 lithological character, and that in some places they intersect one 

 another, we may safely infer that they are of different geological 

 ages, and many of them may be contemporaneous with the 

 basaltic plateau of County Antrim. 



Still proceeding in the direction of Cultra pier, we come 

 abruptly upon a set of stratified rocks, dipping northward at a 

 higher angle than the former. The different character of these 

 rocks at once strikes us ; and as they are found a little further 

 on to be fossiliferous, and the species referable to the Carboni- 

 ferous series, it is evident that there is a fault in the section, 

 bringing up these beds into juxtaposition with the Triassic (new 

 red) sandstone. This fault is supposed, by the officers of the 

 Geological Survey, to be an upthrow to the east of about 300 

 feet, but how the figures are arrived at it is difficult to see, as 

 there appear to be no data upon which to base a calculation. 

 These Carboniferous rocks continue along the shore for upwards 

 of a mile, and consist of thin-bedded limestone, red and grey 

 shales, sandstones, and clays. A few of the bands are fossil- 

 iferous, and specimens of Modiola MacAdami and other species 

 were obtained. 



A little to the north of Cultra bathing-place, and at about 

 half-tide, buff Magnesian Limestones occur. The stratification 

 of these beds is somewhat obscured by sand and shingle. It was 

 to the examination of these beds especially that the Club wished 

 to give attention, but the incoming tide left too little time 

 for this part of the work. Afier a short search, fossils were 

 found in them, but rather obscure for determination. They are 

 interesting, however, as belonging to the Permian series — a 



