1864.] TATE CEETACEOTJS ROCKS OE IRELAND. 15 



EXPLANATION OF PLATES I. & II. 



Illustrative of the Fossil Corals of Jamaica, 



Plate I. 



Fig. 1. Heliastrma cyathiformis: a, corallum, natural size; b, calice and inter- 

 calicular spaces, magnified 4 diameters. 



2. Porites Reussiana : calices, magnified 4 diameters. 



3. Flabellum exaratum : side view, natm-al size. 



4. Placotrochus costatus : a, corallum, natural size ; b, the calice of a young 



specimen, magnified 3 diameters. 



Plate II. 



Eig. 1. PlacocyatJms Moorei: a, corallum, natural size; b, septa, pali, and colu- 

 mella, magnified 2 diameters ; c, costse, magnified 4 diameters. 



2. Thysanus elegans: a, costa, magnified 6 diameters; b, large paliform 



tootli on a dentate septum, magnified 6 diameters. 



3. Stylophora graniilata : calices, magnified 6 diameters. 



4. Antillia Walli : a, side view, natural size ; b, calicular view, natural size 



(the specimen is fractured) ; c, the structure of the wall, endotheca, and 

 epitheca, magnified 2 diameters. 



On the Correlation of the Cretaceous Formations of the North- 

 east of Ireland. By Ealph Tate, Esq., F.G.S. 



[Plates III.-V.] 



Contents, 

 I. Introduction. , 3. Upper Chalk 



Chloritic Chalk. 

 b. White Limestone or Hard 

 Chalk. 

 Table showing the Distribution of 



II. Absent Formations, 



1. Oolitic Strata. 



2. Lower Greensand and Gault. 



III. Review ofthe Writings of previous 



Authors. I the Species 



IV. Descriptions of the Formations. i VI. Palasontological Summary. 



1. Preliminary remarks. | VII. Conclusions. 



2. Hibernian Greensand. ! VIII. Descriptions of New Species. 



a. The Glauconitic Sands. 



b. The Grey Marls and Yel low 



Sandstones with Chert. 



c. The Chloritic Sands and 



Sandstones. 



I. Introduction. 

 In a former commmiication I described " The Rhtetic and Lower 

 Liassic Rocks of the neighbourhood of Belfast " *, and I now propose 

 to continue the subject with a description of the strata which sur- 

 mount the Liassic series, namely, the Upper Cretaceous rocks in part. 

 An incentive to study these formations was the knowledge that 

 the results of the labours of the late Robert McAdam, Esq., F.G.S., 

 had been anxiously looked for by many geologists f, who hoped that 



* Quart. Journ. Geol. Soc. vol. xx. p. 103. 



t Oldham, Journ. Geol. Soc. Dublin, Annual Address, vol. iv. p. 97 ; Haughton, 

 ibid. vol. ix. p. 319 ; Forbes, Quart. Journ. Geol. Soc, Annual Address, vol. x. 

 p. Iv ; Huxley, ibid. vol. xviii. p. xxxviii ; Salter, Quart. Journ. Geol. Soc. vol. xiii. 

 p. 84. 



