638 EEPORT — 1881. 



green marls agreed with underlying beds in tlie Keuper, but differed markedly 

 from the overlying Rhfetics ; then there was every appearance of a passage be- 

 tween the green marls and the underlying red and green marls of the Keuper; and, 

 lastly, the green marls, like the rest of the Keuper marls, were practically unfos- 

 siliferous, while with the commencement of the Paper Shales we get the remains 

 of an abundant, and distinctly marine fauna, in part Liassic. 



9. The Great Flain of Northern India not an old Sea-hasin. 

 Bij W. T. Blanfoed, F.B.8., F.G.S., &c. 



The author called attention to the distribution of land in the Indian peninsula, 

 and to the intervention of a vast plain, traversed by the Indus, Ganges, and 

 Brahmaputra, between the Himalayas and other hill ranges to the east, west, 

 and north, and the more or less hilly tracts forming the peninsula itself. The 

 plain varies in breadth from rather less than 100 to nearly 300 miles. 



This plain has constantly been considered, both by geological and biological 

 writers, as the basin of a great sea, that, in Tertiary times, and probably earlier, 

 separated the Himalayan area from the land of the peninsula. Even in some 

 geological descriptions by an officer of the Geological Survey of India ('Itec. 

 G.S.I.' iii. p. 17) the older alluvial deposits of Bengal are classed as marine or 

 estuarine. 



On examining the evidence, however, there does not appear to be a single fact 

 in favour of the sea having at any geological period occupied the Gangetic or 

 eastern portion of the plain. On the eastern coast of India, near the shores of the 

 Bay of Bengal, marine Jurassic strata are intercalated with certain beds containing 

 land plants (Upper Gondwana) in several localities, and the same marine and 

 similar plant'bearing beds are associated in Kattiawar to the westward. But in 

 the only place on the edge of the Gauges plain Avhere the plant-bearing beds are 

 found, no marine fossils are met with. Some older beds of very low meaozoic or 

 very high palreozoic age (Damuda) are found both north and south of the plain, 

 and as they are river deposits, they may perhaps indicate that the intervening 

 country was land when they were formed. At any rate no marine strata 

 accompany them. A great thickness of nearly horizontal basaltic traps in the 

 Khasi hills, east of the Gangetic plain, appears to bo a continuation of the well- 

 known Tlajmahal traps, believed to be of Jurassic age, and if so, these volcanic 

 rocks, which are undoubtedly of subaerial origin, must have extended across the 

 plain north of Calcutta. 



Again, marine cretaceous beds are found on the shores of the Bay of Bengal in 

 two localities at least, and again in the Khasi hills to the eastward, showing that 

 in all probability the coast line extended from one to the other, but no trace of 

 such beds is known to occur on the edges of the Ganges plain. 



Eocene (nummulitic) rocks of marine origin occur throughout the western 

 margin of the Indus basin in Sind and the Punjab, and extend across the north of 

 the latter to- the spot where the Jumna leaves the Himalayas; east of this they are 

 only found in one locality in Kumaon. Thence for 1.3 degrees of longitude not a 

 trace has been discovered, nor do they recur until the Guro hills are reached. To 

 the east of the Indus plain also nummulitic limestone occurs, but none is found 

 along the southern side of the Ganges plain. Marine, oligocene, and miocene beds 

 are met with as far north as the frontier between Sind and the Punjab, but have 

 not yet been traced further north with certainty. Marine pliocene beds are only 

 met with near the coast. 



The distribution of marine Tertiary rocks therefore indicates that in Eocene 

 times the sea occupied the whole Indus valley as far as the Himalayas, and an 

 arm must have extended to the region now drained by the Upper Indus in Tibet, 

 as nummulites have been foxmd there; but there is no evidence of any sea having 

 occupied the Gangetic or eastern portion of the plain. It is scarcely probable, if a 

 nummulitic sea occurred throughout the whole Indo-Gangetic plain, that a fringe of 

 nummulitic deposits, continuous over many hujidreds of miles, should surround 



