Murchison s Silurian System. 227 ■ 



part of the layers of black calcareous shale which divide 

 the beds of limestone. The black limestone in which these 

 remains are found is overlaid by a sandstone which separates 

 it from the productive coal beds, and is underlaid by strata 

 belonging to the lower limestone. 



Mr. Murchison particularly alludes to a specimen of Li- 

 thosortion fioriforme, a species of coral two feet five inches 

 broad, by one and a half high, which appeared in a quarry to 

 retain the original position in which it grew, and conveyed 

 the impression that it had remained undisturbed beneath the 

 sea, while fine red sand at one time, and mud at another, 

 were deposited around it. 



These corals are also found in the limestone of the Cherra 

 Ponji coal measures ; and in a large heap of limestone col- 

 lected by Mr. Inglis of Chattack for the purpose of burn- 

 ing for lime, I found the first fossil I had observed in a simi- 

 lar rock in India, thus indicating the presence of a coal 

 district. The object of the journey would not however 

 admit of my visiting the quarry, but there can be no ques- 

 tion that the rock alluded to is connected with the nu- 

 merous indications of coal formations that have been found 

 in that vicinity. One other corresponding character may 

 be mentioned between the Cherra Ponji coal beds and those 

 of Coalbrook dale, namely, that the coal measures do not 

 graduate downwards into the older rocks. The limestone 

 of Cherra, which alternates with beds of sandstone and 

 shale, seems to rest immediately on the old red sandstone, 

 as in the Coalbrook dale beds. Mr. Murchison observes that 

 the carboniferous limestone has not in Coalbrook dale any 

 regular downward passage into the old red sandstone, as 

 in other districts ; on the contrary, the old red terminates 

 at the southern end of the tract, and has never been found 

 beneath the coal measures. On the north bank of the 

 Severn the underlying stratified rocks throughout the pro- 

 ductive coal field consists of various members of the Silurian 



system. 



2 H 



