1876-1877.3 253 



ravines and glens cut through the escarpment by the rapid streams 

 flowing down from the hills to the river Lagan and Belfast Lough. 



The reader stated that in the present paper he purposed detail- 

 ing a few observations made during his study of the Cretaceous 

 strata of the Black Mountain, reserving, for some future occasion, 

 a detailed sketch of the part lying north-east and north of Belfast. 



The general geological features of the Black Mountain are 

 shown in the accompanying longitudinal section,* from Colin Glen 

 to Crow Glen. It is drawn from personal survey, and those rocks 

 only are noted about the occurrence of which there is no uncer 

 tainty. The scale of length is about one inch to a mile, but the 

 vertical thickness of the formations is not drawn to scale, the 

 Cretaceous and Liassic strata are exaggerated in order to bring 

 them out more distinctly. The section gives the ground plan as 

 far as it possibly could be delineated in a section of this kind, and, 

 of the numerous faults and dislocations of the strata, only the most 

 important are indicated by black lines. A page plate of vertical 

 sections of the most interesting places along the escarpment is 

 given in order to show the minuter details and succession of the 

 various beds. The scale of thickness appended to these sections 

 refers only to the Cretaceous rocks as a whole : some of the minor 

 sub-divisions being very variable in thickness, whilst others are so 

 thin as to require exaggeration in order to give them their position 

 in the section. 



Before giving the details of these sections, the author noticed 

 at some length the underlying rocks, which he said consisted of 

 the Bunter sandstone — a thick-bedded soft red rock, with layers 

 of brown and yellowish sands, well shown in Conway Street, 

 Belfast, and at Milltown and other places. These sandstones are 

 overlaid by a thin course of buff, and reddish-brown sandstone, 



* The Committee of the Club desire to express their obligations to the 

 author (Mr. Wm, Gault), who has kindly supplied them with the plates in 

 -illustration of this paper. 



