Page:Journal of the Asiatic Society of Bengal Vol 4.djvu/323

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1835.]
and Site of Fossil Bones in the Jumna.
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has caused infinite trouble, not only by the interruption a body of any sort must be to the navigation in such a place, but by the irregularities of its surface (forming the bed of the river), acting as receptacles for the moving kankar and other extraneous substances passing over it, in which have formed irregular masses of conglomerate rock occupying two-thirds of the whole width of the river. These, perhaps, at the time of their formation did not stand more than a few inches above the bed of the river, (the upper surface of the sandstone rock,) but the river deepening its bed in the course of ages has gradually worn away the sandstone, leaving the masses of conglomerate (on which it can make no impression), in the awkward and dangerous positions which they now occupy, with deep water all round them; and although some of the most dangerous have been removed, the passage down with a side wind is often impracticable to the clumsy boats used on the Jumna. It has this advantage over Karim Khán, (the worst pass in the river,) that the stream is not near so rapid.

Those portions of this stratum which lie near the edge are exposed to the effects of the stream in a minor degree, and stand from one to five feet above the lowest levels, presenting peaks and heads of masses at irregular intervals over a space of about 500 by 200 yards. The exteriors of these are of a dirty green colour, which penetrates about one-eighth of an inch, and is, I imagine, caused by the action of the atmosphere. Under this coating, the natural colour of the stone appears, varying between every tinge of yellow and red, and pure white, which would indicate the presence of some portion of iron; but one sight of the accompanying specimens will convince you, Sir, that but for the presence of some consolidating medium, the sand of itself would never resist the action of any stream. This consolidation occurs in the shape of numerous veins, from one-fourth to two inches in thickness, and from three inches to many feet in width, passing through it in every direction, and rendering it quite impervious to the stream with which it has to contend; and from the feeble attempts of which it is in fact defended by some masses of volcanic origin, which are described below. These veins (spec. 2) are either the deposit of some ferruginous spring, which has had a passage over the stratum, and on which the sand has from time to time accumulated, or is a lignitious lava; they occur in every position, horizontal, vertical, and at every possible angle with each of these: their outer edges are black, and bear a very high polish, produced by the action of the water. The fracture presents an appearance which would justify the conjecture of this substance having passed into the present position in a state of fusion, as it encloses a substance within itself, having a vitrified appearance.