1853.] Report on the Geological Structure of the Salt Range. 365 



second subsidence must have occurred to admit of the formation of 

 the upper carboniferous beds which in some places contain brachio- 

 poda in abundance. By the gradual accumulation of calcareous and 

 sedimentary matter, these seem again to have been brought near 

 the surface, and dry land must have existed at the commencement 

 of the oolitic series on which delicate ferns could support existence. 



Succeeding the beds which contain these, we have the oolitic grits 

 and shales, with fragments of large coniferse which incontrovertibly 

 prove the existence of land from whence the wood, &c. had been 

 drifted. As we ascend in the oolitic series the wood becomes scarcer 

 and as terebratulse occur in the upper limestones and belemnites and 

 ammonites in the upper shales and green sandstone, it seems proba- 

 ble that soon after the commencement of the formation, a third sub- 

 sidence occurred, by which the strata were sunk to a considerable 

 depth under the sea, from which they did not emerge until towards 

 the close of the nummulite limestone formation. By a gradual and 

 local deposition of calcareous matter along a particular line, similar 

 to the manner in which coral reefs are formed, a sea barrier may 

 have been raised, inside which in an inland fresh-water sea, the mio- 

 cene strata have probably been deposited. 



The occurrence of small water-worn boulders of nummulite lime- 

 stone cemented by calcareous sand into a conglomerate which forms 

 the lower member of the miocene beds in the Salt Range, indicates 

 the existence of a beach where they may have been formed by the 

 lashing of the waves. 



As all the strata seen in the Salt Eange repose conformably on , 

 each other, it appears to us certain that from a position of compara- 

 tive horizontality they have all been upheaved subsequent to the 

 deposition of the miocene strata. The upheaving force seems to 

 have extended from east to west, the direction of the Eange corre- 

 sponding to the strike of the strata. Whether this has been exerted 

 by the agency of plutonic or igneous rocks, we have no means of 

 judging, as no rocks of the kind appear in the Salt Eange or its 

 neighbourhood. 



Between Ehotas and mount Tillah the elevating force has raised 

 the miocene strata into an anticlinal ridge. Along the line of this 

 mountain, however, to the westward it has been exerted with greater 

 violence, having produced a fracture of the strata along the line of 



3 A 



