Lia« Limestones of India. 89 



in the lias what appeared to him to be the fragment of a gry- 

 phite. The only well marked specimen of a shell which I have 

 been enabled to procure, was a fragment of a bivalve, apparently 

 nearly allied to the Pecten ; but on this subject I shall not en- 

 large at present. It is sufficient to observe, that it is more from 

 a consideration of their geological position and mineralogical 

 characters, than from their contained organic remains, the infe- 

 rence has been drawn, that these limestones belong to a forma- 

 tion identical with the lias. The subject is still involved in much 

 doubt and obscurity. Besides alumina and oxide of iron, these 

 limestones contain a small proportion oi" carbonate of magnesia, 

 associated with the carbonate of lime, — an association, however, 

 which appears common to almost all the limestone formations of 

 central India, from the primitive marbles or dolomites down to 

 the imperfect rock formation known best by its local name of 

 kunkur. A perfectly pure carbonate of lime I have not yet 

 observed, though I have analyzed a considerable number of spe- 

 cimens of our finest marbles, as well as limestones from different 

 parts of the country. 



The formation under review is an extensively distributed one ; 

 it generally occupies plains and low lands through which pro- 

 trude hills of sandstone. The depth of its beds would not 

 appear, in any situation hitherto examined, to be great ; and 

 it has probably been subjected in a most destructive deo-ree to 

 the agency of those great denuding causes which are supposed 

 to have exerted their energies with such amazing force over the 

 whole surface of the globe. At least, this is the easiest way of 

 accounting for the total disappearance of such limestones from 

 many of our sandstone plateaus, and for the irregularity of the 

 patches, often insulated and detached, in which they occur. 

 The limestone, as well as the sandstone strata, are occasionally 

 much inclined in the neighbourhood of the primitive I'ocks, and 

 m many situations have obviously been subjected to much vio- 

 lence and distortion. 



To Professor Jameson. 



