358 



[Proo. B.N.F.O., 



Proceedings. 



SUMMER SESSION 



SCRABO HILL. 



The Geological Section held its first excursion of the season 

 on the 23rd April. The members left by the 2-30 p.m. train for 

 Newtownards, and a short walk of a mile brought them to the 

 south quarry at Scrabo Hill. It is in the quarries on this and on 

 the eastern side of the hill that the best exposures of Triassic 

 sandstone, more than 100 feet in height, are found. The rock is 

 white, grey, and light purple in colour, with thin divisions of red 

 marl or shale. These sandstones are capped by dolerite, and are 

 also traversed by numerous intrusive sheets and dykes similar in 

 character to the Antrim Tertiary basalts, especially to the intrusive 

 sheet of Fair Head. The dolerite at the top overlying the 

 sandstone has long been considered as an outlier of the plateaux 

 lavas of the Antrim district, but it has recently been suggested that 

 it may have been intruded as a sill, and that the overlying 

 sandstone has been removed by denudation. On the face of the 

 rock at the entrance to the south quarry a particularly fine example 

 of current bedding was noted, and some time was spent at the 

 quarry itself collecting hand specimens of sandstone, showing ripple- 

 marks, sun-cracks, current bedding and brecciation, while later on, 

 in another quarry, one specimen showing rain-pits was obtained. 

 The party then moved on to study the remarkable intrusive sheets 

 traversing the sandstone, which are exposed in the face of the quarry 

 as dark wavy bands of basalt, the whole being intersected by a 

 vertical dyke of later age. Specimens were secured of dyke, sills, 

 and adjacent sandstone. In another quarry to the north-east, 

 known as the " North Quarry," but not really to the north of the 



