»j(j(j A. 1$. Wrj£NE ON THE PHYSICAL 



sively limestone accumulations of the Upper Punjab Eocene period ; 

 but it is not until the hills south of the Peshiwur valley are reached 

 that thin layers of conglomerate are found in these beds. 



Gradual and local changes of level in the Eocene area surrounding 

 the Rawal-Pindi plateau appear to be the most probable causes for 

 the local and fluctuating character of these Nummulitic deposits. 

 The outer part of the hill region to the north would seem, at all 

 events, to have been at one part of the Eocene period deeply sub- 

 merged, and again to have received in shallower water the mechani- 

 cally formed sediments from some adjacent land, probably situated 

 towards the Himalayan area. Land also seems to have existed near 

 the Salt Range, whence the vegetation to form, its coal-beds was 

 derived. Towards the close of the ISTummulitic limestone period in 

 the last-named region, from the occurrence of some conglomeratic 

 layers at the top of the group made up of flints and fragments of the 

 limestone itself, a portion of these rocks must have been brought 

 within reach of denudation, though no disturbance sufficient to pro- 

 duce discordance where the conglomerates are found took place. 



Slight elevations such as this may have been the commencement 

 of the grander actions of the same kind which subsequently 

 occurred. 



Tertiary Sandstones and Clay Series. 



19. The rocks of this series occupy by far the largest area of the 

 district under notice, forming nearly the whole of both the Rawal- 

 pindi plateau and the hilly outer Himalayan tract of Jamu-Kash- 

 mir. They have also the greatest strati graphical thickness of any 

 of the better-known formations, amounting in the aggregate, upon 

 a reduced estimate, to between four and five miles ! 



I have already described these rocks in a former paper to the 

 Society, and need only say that their monotony of character enables 

 a sufficiently clear general idea of them to be conveyed in a few 

 words. 



The lowest beds, which intercalate with the jSTummulitic rocks 

 along the outer edge of the northern hill country, are purple and 

 grey sandstones and red and purple clays, forming the Murree 

 group. Succeeding to these are grey (Siwalik) sandstones and red 

 clays, the red colour of the latter gradually giving place upwards to 

 brown and orange ; and the sandstones, after becoming conglomera- 

 tic, change into strong conglomerates of hard rounded crystalline 

 pebbles, derived from the waste of Himalayan rocks. Mammalian 

 and reptilian remains occur throughout, even occasionally in the 

 Nummulitic beds below*, but are rarely of much palseontological 

 value, except in the Lower Siwalik subdivision, where the largest 

 numbers and most unique forms have been found. 



The groups which I formerly describedf are now thus classified, 

 in descending or natural order : — 



■* Eecords Geo]. Surv. Ind. vo 1 . ix. p. 87. 



t Quart, Journ. Geol. Soc. to 1 , xxx. pp. 66, 67. 



