360 'Report on fhe Geological Structure of the Salt Range. [No. 4. 



suitable for the maintenance of numerous huge mammalia, the remains 

 of which, now entombed in rock, must, judging from their appearance, 

 have been transported to a distance from the spot where they died. 



That plutonic, metamorphic and igneous rocks must have formed 

 the district, by the disintegration of which the materials forming the 

 miocene strata have been derived, every one must admit, and as the 

 boulders found in the conglomerates are small and such as we see 

 now carried down by streams from Indian mountains during ordinary 

 floods, we think it probable that the district in which the miocene 

 beds occur, must have presented a range of mountains skirted at 

 their base by a grove of forest capable of affording food to large 

 pachydermata, and washed by an extensive fresh-water lake, in which 

 the saurians, &c. whose teeth occur in the sandstone, could live 

 and flourish. Into this, floods from the surrounding mountains 

 transport boulders of rock, gravel and sand as well as the remains 

 of land animals and trunks of trees. A succession of floods over an 

 extended period would, we conceive, supply material for the forma- 

 tion of strata similar to the miocene beds we are considering. 



It is not at all improbable that the sea may have had occasional 

 access to our supposed lake, indeed the saline incrustation on the 

 sandstones, &c. where they approach the nummulite limestone (an 

 undoubted marine formation) strengthens this idea. 



The absence, however, of marine shells, or other remains which 

 exist so abundantly in the inferior strata, completely, we conceive, 

 refutes the supposition that the miocene strata have been deposited 

 in " a true sea bottom," an opinion, which as regards the Thibet 

 tertiaries in which no marine organic remains have been found, 

 Strachey seems disposed to adopt, while at the same time he admits 

 " that there is no direct proof that these beds are marine." 



When we consider the fragile character, and we believe compara- 

 tive scarcity, in northern India, of land or fresh water shells, it is 

 not surprising that they should so seldom occur in the miocene 

 strata. The Physse, Pupae, and Helices, which abound over the Salt 

 Eange hills, are very rarely to be found in the alluvial deposits at 

 their base, and the fact that rain water charged with carbonic acid, 

 which it always acquires by passing through vegetation, is a most 

 powerful solvent of carbonate of lime may explain in a great mea- 



