20 PKOCEEDINGS OP THE GEOLOGICAL SOCIETY. [NoV, 9, 



Sharpe* (1853) regarded the White Limestone as of the age of the 

 Upper Chalk. 



Jukes t (1862)'refers the "White Limestone to the Upper Chalk, 

 and regards the " Mulatto " stone as of Upper Greensand age. 



King J (1863) parallels the '' Antrim Mulatto stone" with Upper 

 Greensand, and the " Antrim White Limestone " with the Dover 

 Lower Chalk. 



Those authors who have compared the Irish Cretaceous fossils 

 with those of the English Cretaceous heds have referred the former 

 to the Upper Greensand and the Upper Chalk, very properly dis- 

 regarding the hiatus existing between them. Others, guided only 

 by stratigraphical succession, have referred the beds overlying the 

 Upper Greensand to the Lower Chalk, the same being the next 

 above, in the order of superposition. 



IV. Descriptions of the Formations. 



1. Preliminary remarks. — From the foregoing resume of previous 

 memoirs, it is apparent that there stiU remains much to be done for 

 the correct identification of the Cretaceous beds of the north-east of 

 Ireland, which are invested with additional interest on account of 

 their occupying an isolated area, being the most north-westerly 

 Cretaceous deposits in Europe. " The most northerly point in the 

 whole earth, in which Chalk has yet been found, is in the vicinity of 

 Thistedt in Jutland, 57°, or in that of Aberdeen ; the last appears in 

 the south coast of the Island of Rathlin " §, oif the coast of the county 

 of Antrim. The most westerly points in Ireland where Chalk is 

 found in situ are Benyevenagh and near Dungiven, co. Londonderry, 

 in long. 6° 55'. 



2. Hibernian Greensand. — I propose this name for the Cretaceous 

 heds underlying the Upper Chalk of Ireland, the term Upper Green- 

 sand, as used in England, not being sufficiently comprehensive, as 

 the Irish strata may more perfectly be correlated with the " etage 

 Cenomanien " of D'Orbigny. 



The Hibernian series forms three lithological zones, each with its 

 own suite of organic remains ; but the upper part of the third, or 

 highest, zone, though agreeing hthologically with the lower portion, 

 I associate with the Upper Chalk. With this reservation, I purpose, 

 first, to describe the series according to its lithological divisions, and 

 afterwards to notice its fossils. 



The Hibernian Greensand may conveniently be studied in most of 

 the glens of the Antrim Hills ; and I have selected as a type-section 

 that naturally exposed in the Woodburn stream, by the Priest's Hole, 

 on the Carrickfergus Commons. 



a. The Glauconittc Sands. — These sands are of a dark-green co- 

 lour, and consist of glauconitic and arenaceous grains in a slightly 

 argillaceous paste. Throughout the district they present the same 



* Monograph of Cretaceous Mollusca, p. 47. 



t Manual of Geology, p. 622. 



X Synoptical Table, 5th edit. 



I Quart. Jom-n. Geol. Soc. vol. vi. pt. 2. p. 22. 



