Over these, and resting unconformably upon them, cotnes the most widely distributed series of stratified rocks to be found in India,—the so-called Vindhyan system. This immense series of hori zontal sandstones and shales extend from Sasseram and Rotasgarh on the Sone, to the borders of Mewar, and from A,gra to the Nerbachla valley, with several outlying patches in Southern India., as at Ilhitna and Ktumool. All the diamonds found in India seem to be derived from a pebble bed at the bottom of the Vindhyan series, but the diamonds occur simply as water-worn pebbles, so that their original matrix is still unknown. That such an immense area of perfectly undisturbed and quite unaltered rock should be totally devoid of fossils, is very puzzling to the geologist, yet such appears to be the fact. The only explana tions of it that can be given, are either that the Vindhyan rocks were deposited before the begin ning of life on the globe, or that there was some thing inimical to life in the composition of the waters in which these rocks were formed. There is no evidence whatever, except the mere absence of life, that either of these explanations is correct; but, on the whole, it seems most probable that the Vindhyan strata. were deposited in fresh water, at a time when the dry land and the waters enclosed by it were without life, although some kinds of living beings may have exiated in the contemporaneous seas.
Resting in hollows of the ancient gneiss or the Vindhyan rocks, are found the firat fossiliferous strata of the Indian Peninsula, those of the Gondwana system, or the Indian coal measures. These rocks extend in patches from West Bengal through South Rewa and the Nerbadda valley to Cutch, and they aro also found in the valley of the Godavery, and att far south NI Madras. A small outlier of the same series has been discovered at the base of the Himalaya, near Darjiling, almost the only instance of a Peninsular rock occurring in the extra-Peninsular area.
At the bottom of these rocks, wherever the base can be seen, is found a peculiar conglomerate, con sisting of boulders, many of them of large size, embedded in a fine matrix. Some of these boulders aro marked with parallel strife on one or more sides, and the appearance of the whole stratum is that of an ancient boulder-clay deposited from icebergs. Similar rocks are observed in S. Africa and in the Permian formation of Europe, and it is probable that these Talchir beds are of Permian age. Above the Talchirs lie the coal -Ixatring strata of Karharbari, and the Datnuda series of coal-bearing beds found here and there over the country from Raniganj to the valleys of the Ner badda and Wardha rivers. These aro no doubt
economically the most important of the Indian strata, though they cover a very small area com pared with that occupied by the Vindhyan rocks or the ancient gneiss.
The coal-bearing strata contain numerous plant remains, and a few skeletons of terrestrial animals belonging to the amphibia, but not a trace of any marine fossil has yet been discovered in them. There has been a good deal of discussion about the age of these beds, and of those overlying them, the Panchets, Jubbulpur bed, and Mahadevas, because the fossil ferns they contain resemble on the one hand those of the Trias of Europe, and on the other they arc very like those found in the true carboniferous rocks of Australia. The lower rocks of the coal-bearing series are supposed by Mr. Blanford to be of Permian or carboniferous age, and the upper ones (Pauchet) Triassic. There can be no doubt about the proper geological horizon of the uppermost plant-bearing beds,— those of Cutch and Rajmahal,—which are dis tinctly Jurassic in their fossils, and contain in Cutch marine animal remains, such as ammonites of Jurassic age, interstratified with the plant beds. Of the Cretaceous rock, only a few detached areas exist in the Indian Peninsula, and these are all, with the exception, of some beds at Bagh near Indere, within a few miles of the present coast.
Overlying the cretaceous rocks of Bagh, and overlaid in turn by the Eocene beds of Gujerat, are the great horizontal sheets of the Dekhan trap, —the greatest accumulation of volcanic rock known in the world. The trap extends in the uorth and south direction from Belgaum to Nerauch, and spreads from Kattyawar on the west, to Amarakantak on the east, covering every kind of rock, from the l3undelkhand gneiss to the most recent cretaceous formations, with its great horizontal lava flows, and in parts of the Western Ghats it is more than 4000 feet thick. It has been surmised that the lava must have been ejected on dry land, and not under water, because in some parts, as near Naldrug, the upper part of nearly every flow is full of vesicle, now occupied by zeolites and other minerals. How this could have been accomplished so as to leave all the beds nearly horizontal, and without trace of a single volcanic cone, is not apparent. But Dr. John Grant Malcolmson, who in the early part of the 19th century described this great volcanic outburst, discovered in the Gawilgarh trap many casts of marine shells.