6 



PROCEEDINGS OE THE GEOLOGICAL SOCIETY. 



[Nov. 9, 



fossils distinguisli this series, and the Shells, Foraminifera, and Corals 

 have been already in part described*. 



Fig. 4. — Section on the coast of Vere. 



1. Wliite limestone. 



2. Miocene shales, sands, and marls, Hglily disturbed. 



Fig. 5. — Section from Bowden to the Blue Mountain Region, near 



Bath. 



Bowden. Plantain Garden River. 



Sea 2 1 2 7 



1. Wliite limestone. 2. Miocene marls and sands. 



7. Altered conglomerate and Cretaceous rocks mixed with dykes. 



The beds of Bowden, Yere, and Uj)i3er Clarendon, whence the 

 Corals about to be described were derived, are included in this for- 

 mation. Although less disturbed than the preceding Cretaceous and 

 Eocene groups, still the Miocene strata have not escaped the great 

 movements which have affected the island. Thus this fossiliferous 

 group may be observed on the coast of Yere in a vertical position, 

 with the white limestone resting almost horizontally upon it. A 

 thickness of less than from 500 to 600 feet can scarcely be attri- 

 buted to this series. The White Limestone (a great succession of 

 beds, or rather masses, of friable, compact or semi crystal line lime- 

 stone) covers by far the greater part of Jamaica ; it is at least 2000 

 feet thick, and is in some places highly inclined, in others horizontal, 

 in some conformable to the sands and marls, in others not so, whilst 

 frequently it rests on a base of ig-neous rock, without the intervening 

 Cretaceous, Conglomerate, and Lower Miocene strata. The White 

 Limestone contains but few fossils, and these are often in the state of 

 casts. It would appear that, after the emission of great masses of por- 

 phyry, beds of the Hippurite- cretaceous age were formed, elevated, 

 and broken up, and often metamorphosed by contact with dykes of 

 syenite f. During the latter period great masses of conglomerate were 



* J. C. Moore, P. M. Duncan, and T. R. Jones, Q.uart. Journ. Geol. See. 

 Tol. xix. p. 510. 



t As regards the influence of the proximity of igneous dykes and masses upon 

 the stratified rock, it is to be observed that it is at fii'st to obUterate or confuse 

 the evidence of their sedimentary or detrital origm, and eventually to induce a 

 more or less crystalline texture. Thus in many rocks which were originally 

 conglomerates, the distinction between the matrix and the included boulders 

 has quite disappeared, a honiogeneous texture being presented resembling a fine- 

 grained porphyry, or even certain varieties of trachyte. The calcareous rocks are 



