514 Report on the Salt Range, [Nov. 



with pyrites, having during the oxidation of the latter undergone spon- 

 taneous combustion, a phenomenon of frequent occurrence, and one 

 which has produced much mischief in some of the British collieries. 

 From the^shales" downwards to the base of the hills on the S. "W. side, 

 there is a development of calcareous strata evidently superior in geolo- 

 gical position to the red saliferous marl, and which we have observed no- 

 where in the range to the same extent. 



In contact with the shales is a calcareous sandstone which gradually 

 passes into strata of limestone of a light bluish-grey color, containing 

 abundance of nummulites, and towards the base of the hills enclosing 

 layers of flints. These latter have a brownish tint, derived from 

 peroxide of iron, with which they are frequently incrusted, but in none 

 could we detect organic remains, which abound in the limestone, and 

 particularly in its lower strata, which are of a much darker tint, and 

 coarser character, than the upper beds. From the former we obtained 

 several specimens of shells of the genera Productus, Terebratula, and 

 probably one Spirifer, associated with Ammonites, Belemmites, &c. The 

 appearance of these fossils, as well as of the limestone in which they are 

 imbedded, is more ancient than that of any of the other fossiliferous 

 strata we have noticed. Shales of the genera Productus and Spirifer 

 are generally considered characteristic of strata inferior to the Lias, and 

 abound in the magnisian limestone. There are however exceptions to 

 this, and at least 3 species of Spirifera, and we think one or two Producti 

 have been found in the Lias itself. Terebratulse are by far the most 

 abundant of all the fossils we noticed in the limestone, and this genus 

 has been found to occur th rough all the strata from the chalk forma- 

 tion downwards. 



At first sight we were inclined to believe that we were dealing with 

 magnesian limestone, but on subjecting a portion of it to chemical ana- 

 lysis, we failed to detect any magnesia in its composition, which earth 

 does not, as far as we can ascertain, exist in any limestone of the salt 

 range. 



We regretted much that our time did not permit us to examine this 

 interesting deposit more thoroughly, as we are satisfied that from it a 

 very fine collection of Fossil shells could be made, by which the true age 

 of the calcareous strata might be established. In the ravine where the 

 coal is seen beautiful sections of the strata are exposed to view, which 



