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change of the nature and weight of materials. All these conditions, and the frequency of ripple marks, indicate a shallow sea easily influenced by heavy out pours of muddy waters from the land. The thickness of the Jurassic rocks vary veries much, and the extent of the beds is limited to very small areas, compared to those of the Carboniferous. This is probably due to the deposition taking place in creeks of a deeply indented coast, and in great part to the oscillations of the land and sea bottom, causing in some localities repeated denudation of materials newly deposited, and in others a steady sinking and consequent thickness of formation. The fossils being frequently much deformed, is a good evidence of these oscillations having taken place.

The Jurassic beds have always been considered conformable to the Carboniferous. I am inclined to believe that this conformity is only apparent. The dip of both formations is generally great, seldom under an average of 45°. In such highly up-tilted beds, a difference of a few degrees is not easily appreciated, unless a careful measurement is taken, and I fancy that most writers have been satisfied with an approximation. However this may be, there is no doubt that the Jurassic limestone presents, in very many places, indeed in most, the appearance of having sustained very sharp local upheavals, soon after the end of the Secondary period, but of little extent; and here again we find the salt, gypsum and red marl always underlying these sharp and dome-like anticlinals. We remember how Sheikh Bodeen is thrown into a succession of short, gothic, arch-like anticlinals; and that under the Jurassic beds the Saliferian are to be seen, perfectly conformable to the limestone and following it in all its oscillations. At Maree on the Indus, a similar appearance occurs: thick masses of salt, gypsum with bi-pyramidal crystals, quartz, red marl and magnesian mud stone more or less cellular, support a very sharp anticlinal of Jurassic limestone; and the Saliferian and Jurassic are conformable not only in general dip, but in all the details of the fold. Moreover, both the Silurian and Jurassic dip S. (2 or 3 degrees E.) and N. (2 or 3 degrees W.) on both sides of the anticlinal dip, which are not the usual ones of the other rocks of that portion of the Salt Range, the Nummulitic and the Miocene dipping N. E.

Whether these local upheavals are merely due to the swelling of

the gypseous beds from the change of anhydrite into common gypsum by absorption of water, is more than I can say. The Saliferian beds would naturally break, dislocate and lift up the superincumbent Jurassic when swelling itself into undulations. We should thus obtain undulated beds of Saliferian and Jurassic. Let such undulated layers be submitted to the lateral pressure which must have accompanied the great upheaval of the Afghan-Himalayan system, and we have the undulations folded into arches and sharp bends.

The Saliferian and Jurassic have been very much denuded, their debris being extremely abundant in some beds of conglomerate and sandstone of the Miocene, especially on the western side of the Indus, in the districts of Kohat and Bunnoo.

94. There are but few traces of the deposits which may have taken place between the Oolite and the Nummulitic, and I have never myself seen any cretaceous rocks in the western Himalaya* or the Afghan mountains, neither have I found any pebbles with cretaceous fossils in the conglomerates of the Miocene. From the development of considerable vegetation in the shales near the base of the Nummulitic formation, it is evident that a steady rising of the land went on during the time of the upper Jurassic and Cretaceous periods, and with such a rising we would naturally associate the great denudation of the Jurassic beds, soon after their deposition. Little doubt can be entertained that during the Cretaceous period, the Himalayan and Afghan islands had become united into a continent of considerable extent, traversed by chains of extinct volcanic ridges, and therefore receiving an abundant rain-fall which caused great denudation. We know how quickly volcanic mountains decay, when once they have ceased to receive fresh supply of ejecta. I believe that the cretaceous beds which have been found in and near the Himalaya are very limited in extent, even more so than the Jurassic beds. The small horizontal area of these Secondary beds contrasts widely with the great superficial extent of the Carboniferous, the Nummulitic and Miocene formations; and yet when they do occur, the Jurassic beds at least have considerable power. A continent with a deeply indented coast appears to be indicated by these peculiarities of the Secondary beds.

* Dr. Stoliczka has found Cretaceous rocks in the mountains of Spiti. Editor's note.

95. The Nummulitic epoch must have been a long one, if we can judge by the thickness of its deposits. There does not appear to have been any violent volcanic action, nor any great and sudden movement during the period, but there was a great deal of very slow and probably imperceptible oscillation. Thus we first find the base of the Nummulitic to be generally a sandstone without fossils,* this is gradually impregnated with calcareous matter, becoming a sandy, very impure limestone, full of shallow water fossils and containing only a few very small species of Nummulites. This has been therefore a period of slow and trifling sinking of the land, and it is probable that the sea never covered it by more than a few feet. Then the oscillation went the other way, and the land appeared again, and was covered by forests. Another slow sinking brought on a fresh incursion of the sea, which soon covered the forests (lignite) with a layer of limestone, full of large Nummulites and other shells. The depth of the sea was greater than before the growth of the forests, but it probably did not much exceed 20 fathoms. Another movement upwards again exposed the land, and again forests grew and formed thin seams of lignite. Again the land sank and the sea covered in the lignite-beds with calcareous mud. At first the depth was trifling, little exceeding 20 fathoms, but the sinking continued to the end of the Nummulitic period, and the limestone assumes more and more the appearance of a deep-sea formation as we get higher up the series. It is, however improbable that the volcanic mountains of the great bars of the Himalaya and Afghan mountains were ever covered by the Nummulitic sea, as no nummulite has ever been found amongst the central chains;† but that sea filled up the whole of the space between the arms of the great everted V formed by the Himalayan and the Afghan chains, and probably also bathed the outside shores of the arms of the V. This slow, gradual and long continued sinking of the land, during the deposition of the Upper Nummulitic formation, accounts for the appearance of no great depth in rocks which have

* Sometimes a fragile limestone with Planorbis, and probably fresh-water. See note to para. 66, chap. iii.

+ Dr. T. Thomson reported having observed Nummulitic Limestone in Little Thibet at an elevation of 16,500 feet. But I much doubt the accuracy of the observation, and cannot help imagining that the Thibet nummulites are, like those of Manus Bal, weathered encrinite rings. See "Introduction,” page ii.

a very considerable thickness; the sinking was, however, greater than the amount of deposit could compensate, and the rocks have therefore the appearance of a tolerably deep sea formation at the top of the Nummulitic series. Then again, we have a long and steady rising of the land, and in consequence a great denudation going on, a denudation which has caused the removal of a great deal of the Nummulitic formation, in localities where sea-currents, high-tides and other unfavourable circumstances assisted in the work of destruction. It is curious to notice on the top of the Nummulitic limestone, how the surface of the rock has been broken by the waves; how the fragments have been rolled and rubbed and then glued together again. This appearance is always seen as a bed of transition between the Nummulitic and the Miocene. A considerable time must have elapsed between the end of the deposition of the bed and the breaking up of it, as we must allow time for its solidification. But at any rate, here, at the beginning of the Miocene epoch, we had the Nummulitic limestone forming a nearly horizontal and far-reaching sea-coast, covered with a very thin sheet of water, rolling and polishing pebbles. But this conglomeratic layer is thin, and we very soon see a large quantity of mud and sand, and pebbles of far distant rocks, brought down to the sea.

96. Let us consider the kind of map we have at the beginning of the Miocene epoch, and we will have no difficulty in understanding the formation of the Miocene sandstone and conglomerates of the SubHimalayan and Sub-Afghan chains. We have an immense expanse of sea, north of the tropic of Capricorn, between the latitudes 90° W. and 90° E., for, in these days, the Andes had not yet surged up and most of South America was under water, as well as nearly the whole of Africa, Arabia, Persia and India. There were probably groups of islands where these continents now stand, but the immense, dry, thirsty plains and plateaux of these countries were then under the sea. There was therefore no impediment to the regular play of the Trade Winds, no monsoons or winds deviated by the rarifying power of arid deserts, but especially no chains of mountains to dry the S. E. trade-winds before their arrival at the equator, and their ascending to become upper currents with a direction to the N. E. At the tropic of Cancer, these winds, still charged with the whole of the

humidity they had sucked from the sea in the Southern Hemisphere, descend again and become under or lower currents, keeping their N. E. direction.* Before proceeding far, these winds meet a couple of ranges of mountains forming a great everted V, opening to the south, and on these ranges they poured such a quantity of rain that a denudation began to take place to an amount nowhere else exemplified. The only approach to this rain-fall is that now observed in Patagonia, a high country which happens to be situated in the Southern Himisphere, somewhat in a position analogous to that of the Himalaya in the Northern Hemisphere during the Miocene epoch. In Patagonia "Captain King found the astonishing rain-fall of "nearly thirteen feet (151 inches) in forty-one days; and Mr. "Darwin reports, that the surface water of the sea, along this part of "the South American coast, is sometimes quite fresh, from the vast "quantity of rain that falls."t

We are now therefore prepared to anticipate a formation composed of coarse debris of the older mountains, washed down by violent torrents; we understand how it is that the waters of the sea lost their saltness, and that marine shells deserted these regions, and are therefore not to be found as fossils, or are at any rate excessively rare. The continual and violent rushing of streams, charged with mud and boulders, did not allow of the development of fluviatile animals; and thus we find the lower Miocene a mass of clay, sand and large boulders, in beds considerably false-bedded and totally free of fossils, with the exception, in a few protected localities, of some bulrushes imbedded in salt. These torrents occasionally tore up forests from the mountain sides in their headlong course, and thus it is that we find here and there small niduses of semi-carbonized wood, interred in the sandstone. masses of conglomerate, accumulated in certain places, are of tremendous size, and probably mark the exit from the hills of the principal torrents of the Miocene Himalaya. The deposit of this coarse debris of the old volcanic chain and of the several deposits which had become gradually accumulated round it, attains a thickness of no less than 5,000 feet, and probably in some places much more. This mass of

The

See for a general explanation of the routes of the winds and the causes which alter these routes, the work of Captain Maury, L. L. D., U. S. N. entitled, "The Physical Geography of the Sea and its Meteorology."

+ Maury's Physical Geography of the Sea and its Meteorolgy. Page 129

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