of the North of Ireland. 171 



lowest member of the trap deposit, which is usually a bed of 

 ochreous bole : the flints so imbedded have usually themselves ac- 

 quired a red tinge, apparently by percolation, from the oxidated 

 iron of the stratum in which they lie. 



This aggregation of flints, bedded in red ochreous bole, forms at 

 Macgilligan, a stratum thirteen feet thick. It may be observed, 

 also, near Larne and near Belfast, and seems indeed of almost 

 universal occurrence. 



List of organic remains found in the chalk of Ireland. 



GENERA. SPECIES. PLACES. 



Echinus .... cidaris mamillata .... Kenbaan Antrim ; SlievegalHon Derry. 



scutatus Pollen quarry near Agenloo Derry. 



Terebratula. . vulgaris Ballyness Derry. 



sulcata Ibid. 



Pecten earless Ballycreem Derry. 



The foregoing specimens closely agree with the fossils of the 

 English chalk. 



Belemnites are common in most of the quarries opened on this 

 bed in Ireland : many of the bodies in the English chalk, once 

 supposed to be belemnites, are now regarded as the pallisadoe 

 spines of the echinus. Some few, however, are undoubted be- 

 lemnites y the Irish specimens appear to be generally true belem- 

 nites. 



Specimens of cornua ammonis, from five Inches to one in 

 diameter, occur in the Pollen quarry j but not having myself ex- 

 amined these, I cannot say how far they agree with some of the 

 very few varieties which are found in the lower strata of chalk in 

 England. The flinty nodules often contain fossils similar to those 

 of the surrounding chalk, and present, in addition to these, traces 

 of alcyonia. 



y2 



