©/• the North of Ireland. 1 67 



E. Mulattoe or Green Sandstone. 



To the general account of this rock given in the Introduction, 

 it may be added, that on treating different specimens with acids 

 they were found to contain about nine-tenths of calcareous matter, 

 the residuum consisting of green chloritic grains, mixed with quart- 

 zose sand or gravel. 



The mulattoe is seen in Colin glen, a valley on the south-west 

 of Divis hill near Belfast, and in several other places on the slope 

 of that mountain ; it is evidently interposed between the slate clay 

 of the lias formation and the chalk. It occurs also at Cermoney, 

 about five miles north-east from Divis. The chloritic grains in 

 the mulattoe of Divis are small and very numerous, the calcareous 

 base greyish and compact j it is traversed by slender veins of 

 calcareous spar : besides the smaller grains of quartz, it contains a 

 few larger pebbles with a reddish tinge. 



Since it is not quarried for any economical purpose, we have no 

 opportunity of ascertaining accurately the thickness or extent of 

 the bed. 



It is seen however near Larne, and considerably further north 

 near Gerron point, occupying a position corresponding to that in 

 which it occurs near Belfast, and it seems highly probable that it 

 extends beneath the chalk throughout the intervals separating these 

 points ; indeed I am inclined to believe that where the series ap- 

 proaches to completeness, this member will seldom be found want- 

 ing. 



In Murloch bay, where the line of chalk commences on the 

 east of the greenstone mass of Fairhead, a thin seam of quartzose 

 pebbles cemented by green sand, affords traces of this formation ; 

 it separates the chalk from a thick bed of red sand. 



