76 Miscellaneous. 



the inferior limestones of the Silurian system. Among these the 

 most prominent are the large Productus hemisphericus, and many co- 

 rals, including Lithodendron sexdecimale (Clodocora of Ehrenberg), 

 which is so abundant that it constitutes the greater 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 Lithosortion 

 floriforme, 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 collected by Mr. 

 Inglis of Chattack, for the purpose of burning for lime, I found 

 the first fossil I had observed in a similar rock in India, thus indi- 

 cating 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 question that the rock alluded to is connected with the nume- 

 rous indications of coal formations that have been found in that vici- 

 nity. 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 productive coal- 

 field consists of various members of the Silurian system. 



" Mr. Murchison concludes his observations on this coal-field by a 

 notice of the faults and dislocations occasioned by trap rocks. The 

 district affords proofs of having been raised up from beneath the sur- 

 rounding new red sandstone in separate wedge-shaped tracts, the 

 most remarkable dislocation being that which bounds the coal-field 

 to the east. The coal-measures along this line are not less than 

 1000 feet thick, and as some of the lower seams of coal are thrown 

 up to the level of the overlying strata of new red sandstone, the 

 upcast is thus shown to have exceeded 1000 feet, though to what 

 further extent has not yet been ascertained. It will be recollected 

 that we formerly explained the elevated position of the Cherra coal- 

 measures in precisely the same way that Mr. Prestwich and Mr. 

 Murchison now account for the great upcast of the Coalbrook dale 

 field*, the only difference in the two cases being, that in India the 



* See Report of a Committee for investigating the Coal and Mineral Re- 

 sources of India. Calcutta, 1838, p. 24. 



