202 



PROF. P. M. DUNCAN ON THE 



The Sindian formations, including the transitional beds with Oar- 

 dita Beaumonti beneath the trap, and the Gaj series at the top y 

 contain 136 species of Corals and many varieties. Of these, 9 

 belong to the transitional series, and 56 to strata in which lummu- 

 lites exist in profusion. The Nari series, with few species of Nurti- 

 mulites and with N. garansensis, a European type characteristic of 

 the Upper Kummulitic or Oligocene, contains 20 species. The 

 Miocene strata of Gaj contain 41 species. I omit from these 

 numbers all species from doubtful localities. Thus, as only one 

 species transgresses, there are five Coral-faunas ; and if the separa- 

 tion I have proposed at the base of the N"ari series is right, there are 

 six in the same area, included in a prodigious depth of sedimentary 

 strata. The study of the Corals does not indicate that there was 

 ever a sea there with a depth of many hundred fathoms ; on the 

 contrary, shallow-water conditions (within 20 fathoms) usually pre- 

 vailed during the slow oscillation of the area, in which subsidence on 

 the whole predominated. 



IY. The Equivalence of the Manchhar Strata of Sind and the 

 SivdlUc Group of the Himalayas. 



The Geological Survey of Sind by Blanford and Fedden has proved 

 that in some places the Manchhar strata succeed transgressively to 

 the Gaj series, whilst in others there has been erosion of the marine 

 deposit before the deposition of the freshwater one, or else the 

 lower group is absent. Bones of Bhinoceros sivalensis have been 

 found in the uppermost Gaj strata. There is no doubt that the 

 greater part of the coralliferous strata of the Gaj series accumulated 

 in shallow water, and yet beyond the reach of the wash-down of a 

 coast-line. But the lower Manchhars were deposited in shallow 

 water within the scope of terrestrial denudation. There must have 

 been considerable general changes in the physical conditions of the 

 area, : and they persisted ; for coral life has never since prevailed 

 there. The first change probably was one of slight general up- 

 heaval ; and subsequently a slow and progressive subsidence 

 occurred, during which the vast vertical development (8000 to 10,000 

 feet at least) of the lower and upper Manchhars accumulated. 



Conglomerates, coloured sandstones (giej, green, and red in tint), 

 and clays, are the prevailing deposits on the inner flanks of the 

 vast mountain-system which surrounds Peninsular India, from Sind 

 to Burma inclusive. Made up of stone brought down by the rivers 

 of the extra- peninsular mountain-system, before it became of very 

 great height, and when its breadth was probably much greater than 

 it is now, these deposits are to be traced to the north of Sind in the 

 Suleiman Mountains, in the Salt range, covering much of the 

 surface of the -Northern Punjab, and then, forming part of the sub- 

 Himalayan range, as far east as the Brahmapootra. Similar 

 deposits are found, in diminished thickness, in the Assam range ; and 

 they became important in the Burmese territories. The Sindian suc- 

 cession of the strata is the normal one ; and it extended to a certain 

 distance northwards ; moreover it is exemplified in the Burmese 



