86 Guide to Belfast. 



cephalopoda, urchins, and sponges. The following are a few 

 species noted: Belemnitella tni/cronata, B. quadra fa, Pleuro- 

 tomaria perspectiva, Echinocorys vulgaris, Ho/aster Icpvis, 

 Ventriculites gibbosus, and Eiheridgia fnirabilis. 



The Chalk is a pure white limestone, with frequent 

 bands of flint lying in flat tabular masses along apparent 

 bedding planes ; in some exposures vertical masses of flint 

 of a roughly columnar appearance are to be seen — referred 

 to as " Paramoudras." 



The following is an analysis of the chalk from Maghera- 

 morne, by Dr. Hodges : 



Carbonate of lime ... ... ... 98.63 



99.64 



The analyses published by Dr. W. Frazer Hume may also 

 be referred to. 



The chalk, as found in our district, is hard and compact, 

 breaking with a splintery fracture, so that even hand speci- 

 mens are somewhat difficult to dress ; planes of bedding are 

 not very evident, except where emphasized by the tabular 

 flints. Fossils are not very numerous, with the exception 

 of Belemnitella mucronata, which is found widespread 

 throughout the district. The other forms are Turritella 

 uuicarinata, Trochus sp., Ostrea vesicularis, Terebratula 

 carnea, Riiynchonella plicatilis. Occurring mainly in the 

 lower portions of the limestone are Mosasaurus gracilis, 

 Echinocorys sciitatus, Holaster planus, Pleurotomaria per- 

 spectiva, etc. Microscopic sections of the chalk reveal the 

 presence of a large number of foraminifera. The chalk 

 powder found in the interiors of many of the paramoudras 

 and nodular flints is a fruitful source of well-preserved 

 foraminifera, and also of siliceous sponge spicules and ostra- 

 coda. The Appendix iii. to the Proceedings of the Belfast 

 Naturalists' Field Club. 1875, may be referred to for 

 " A List of the Cretaceous Microzoa of the North of 



