Lastly, we have to notice the remnants of Blue Trap in Salsette generally, and suffice it to state that, this occurrence is very frequent. The tracts which I have seen are all very small, and in the midst of the Volcanic Breccia; sometimes forming small mounds, and sometimes (as a little to the west of Bandoop) the crests of high hills. In all instances the structure is more or less granular and crystalline, with brown specks which, together with great toughness, indicates that it has been exposed to the influence of great heat. There are no ridges of fresh blue trap as in Bombay, and no extensive tracts even of that which has been just described so far as my observation extends, but this, it should be remembered, has been very limited.

Summing up briefly, then, the geological products of Salsette, -we have the great mountainous tract composed of Volcanic Breccia imbedding here and there masses of compact Blue Trap, and portions of the subtrappean Freshwater Formation of Bombay, which proves that, it was a subsequent effusion to the columnar basalt of the outside of the island and of Coorla; (that basalt being now identified with the " trapitobasaltic" tract of Bombay, which appearing in masses, in the Volcanic Breccia where the latter is in contact with it, has therefore evidently had these masses torn off from it;) a basaltic ridge on the outside of the island, whitish and columnar in the north, black and tabular in the south, overlying conformably in both localities the Freshwater Formation. And lastly, the Shell-concrete underlaid, in some places, by the Blue Clay of Bombay. So that, in fact, while the islands of Salsette and Bombay are of the newer geological products, and therefore, belong to the same category, those of Trombay, Elephanta, and Carinja are composed of the old trappean beds of the Deccan.

It is, however, difficult in all instances, as in the Blue Trap of Butcher's Island and on the western shore of Trombay, to say positively, whether it originally belonged to the old, mainland beds, or, to the new ones of Bombay and Salsette, on account of the altered state by heat of the fragments of the beds of Bombay which are in the Volcanic Breccia, making them look like the older formations. Hence, in Salsette also, it becomes almost impossible, in our present state of knowledge of the geology of that island, to say, which of the beds of trap belong to the old, and which to the newer formations. There are also many parts of the watercourses in Salsette where dykes of the black-basalt are exposed, especially along that leading to the Vehar Lake from Coorla, and afterwards, in those crossing the path to the Caves of Kanheri. How far the geological type of Bombay and Salsette may be continued northwards has yet to be shown.

The island of Bassein, however, which is situated to the north of Salsette, does come within the area of volcanic disturbance that destroyed the continuity of the Western Coast of India at this part and fissured it into the islands abovementioned, and it is the only remaining one which I have not geologically described; but time has not permitted of my visiting it for this purpose, and therefore, it must be left for another opportunity.

There are yet, however, three other little islands that I have to notice here in connection with our subject, viz. Oyster-Rock and the islands of Henery and Kenery. The former (on which a battery is now being built) is situated close to the southernmost part of Bombay, viz. Colaba, and is composed of the Volcanic Breccia; but unlike Cross-Island, Sewree Point, and Antop Hill, which occupy a similar position geologically, on the eastern side of the island of Bombay, it still retains its brecciated form most evidently, while that of the other three places mentioned, is almost lost in the homogeneous, black, jaspideous rock into which a greater heat has transformed it.

The islands of Henery and Kenery, which hardly belong to the estuary of Bombay, being situated out of it, and some little way to the southward on the coast, though always seen on entering Bombay Harbour, are therefore mentioned here. That of Kenery, which is the outermost and largest, is, according to a specimen of it brought to me by a friend, composed of a fine, dark, crystalline, sparkling, granular greenstone, apparently belonging to the traps of the Deccan, from which I also infer that its little neighbour, viz. Henery, is of a similar composition.

Discovery of a Portion of Pegmatite in a Basaltic Dyke in the Island of Carinja. By H. J. CARTER, Esq., F.R.S.

To this discovery I have already alluded in describing the geology of the island of Carinja, where I stated that I should return to it more particularly under a separate head. My object in so doing is to bring the question of the source of the débris which is contained in the Volcanic Breccia of the islands of Bombay and Salsette under consideration, especially in connection with the presence of this portion of Pegmatite in the basaltic dyke of Carinja.

In the month of January last (1861), while examining the geological structure of the mountain called "Great Carinja," I noticed near a basaltic dyke situated in its north-eastern angle, or that part nearest the village of Ooran, a number of pieces of whitish rock, which formed such a contrast with the black-basalt of the dyke and the

brown earthy decomposed trap on both sides of it, that, for the moment, I thought they must have been brought there from a distance. However, my attention having been directed to the part where they were most' plentiful, I at once saw that they came from a portion in the dyke. The dyke was about two feet broad; could be traced for several hundred feet about N. and S.; stood up in places like a low, narrow wall amidst the decomposed trap, and was composed, as before stated, of black-basalt. The fragment of Pegmatite in the dyke was about the same width as the dyke, composed of large white and pink crystals of felspar, with portions of hyaline quartz, and, I think, a little white, glistening chlorite in some parts. At first, I thought it was the end of a vein of Pegmatite, but on carefully digging round the dyke at this part, and exposing the whole in situ, I afterwards found it to be an isolated fragment of this rock. Some parts of it were white and pulverulent, while others were solid and fresh, and so hard and undecomposed, that in the fracture, no doubt could be entertained of the nature of the rock. It was somewhat tinged greenish at the circumference by contact with the black-basalt, but this colour did not extend deeper, nor were the two rocks at all amalgamated. No doubt now remained in my mind that this was a fragment of Pegmatite which had been brought up with the basalt.

This fact having been established, at once corroborated Dr. Leith's discovery of a portion of Diorite in the Volcanic Breccia near Antop Hill, in the island of Bombay, to which I have alluded in my Geology of that Island; and, in my "Summary of the Geology of India," under the head of "Volcanic Breccia,”—have assumed that, much of the débris of this formation, besides containing portions of the sub-trappean freshwater formation of Bombay, (identified by their fossil remains,) consisted also of débris of the provisionally called "Oolitic" sandstones and shales beneath the trap. Still, the altered and decomposed state of these fragments, and the indistinctness of Dr. Leith's portion of diorite, from the blackness of the Volcanic Breccia in which it is imbedded, rendered it very desirable that an unequivocal specimen of rock, brought up from below the trap, should be found. This has now been supplied by the portion of Pegmatite abovementioned, specimens of which are preserved in the Society's Museum.

Aided by this single fact, then, we may account for the greater part of the enormous quantity of débris which is contained in the Volcanic Breccia composing the hills in the north-eastern part of the island of Bombay, and all the mountainous districts in the island of Salsette, without having to recur alone, to the Lacustrine Strata which have been shown to underlie the basalt of Bombay and Salsette, although we have

sufficient data now to show that they also once formed a continuous series of great extent over this part of the Western Coast of India.

Discovery of more Organic Remains and Minerals in the Trap of Bombay. By Dr. LEITH.

Rana. In the month of June 1861, Dr. Leith presented to the Society a piece of carboniferous shale, with the impressions of Frogs' feet on it, which he had found at the " Sluices," among the débris of the sub-trappean Freshwater Formation which had been dug up to form the outlet of the main-drain of Bombay into the sea at this point. Comparing the size of the impressions with those made by Rana Leschenaultii now living in Bombay, Dr. Leith thinks the body might have been about one and half inch in length, and therefore, could not have been made by individuals so small as Rana pusilla.

Cyprides, Pyroxene, &c.—On examining portions of the thin stratum of the Freshwater Formation which is exposed in the great scarp of blue trap in the quarry of Nowrojee Hill at Bombay, Dr. Leith found foliated Pyroxene in black rhombic crystals, about one-fifth of an inch in diameter on Prehnite; also Chabasite, Laumonite, and Dodecahedral calcspar; together with portions of the brown, sedimentary strata bearing the casts of Cyprides.

This thin stratum of the freshwater formation has 90 feet of blue trap, by measurement, above it, and about 40 feet below, which rests on the Volcanic Breccia also containing large fragments of the Freshwater Formation; the stratum between the trap being about 2 feet wide, and the whole scarp about 600 yards long. Wherever the trap comes in contact with the freshwater strata, there is always a great development of the trappean minerals. The presence of the casts of Cyprides here leaves no doubt of the nature of this thin stratum, and the formation to which it belongs, and from which it has been raised into its present position; for there is no gradation of the lower trap into it, as there would have been had it been deposited on it gradually. Soon the hill of trap in which it is situated will be all quarried away, when nothing but this record may remain of the facts above stated.

The raised portion of this stratum of the Freshwater Formation between two such thick beds of trap suggests the question, whether the whole of the Freshwater Formation may not originally have been deposited on some rock below the trap, and afterwards raised into its present position, since, in no place has it as yet, been found to rest on the trap with the usual appearances of having been deposited there.

Section of the Trap in the Western Ghauts. By H: J. CARTER, Esq., F.R.S.

On a cursory examination of the "Bhore Ghaut Incline" cutting, which extends from Lanowly Wood (2,027 ft.), a little beyond Khandalla on the top of the Ghaut, to the bottom in the Concan (196 ft. above the sea), a little to the north of its upper end, so that it traverses the scarp obliquely (for upwards of 15 miles), I could observe nothing but amygdaloid trap, chiefly of a blue colour. Here and there it is less amygdaloid, and therefore more compact; this is particularly the case just below the lower or Great Viaduct.

After passing the great earthwork below the last tunnel, and therefore, close upon the level of the Concan, a large bed of porphyritic trap (black basalt, with tabular crystals of glassy felspar) occurs; but even this is capped by amygdaloid trap apparently all the way into the Concan. This porphyritic basalt is remarkable for the number of geodes it contains, and therefore for the fine specimens of zeolitic minerals it has yielded. Here it is remarkable also for the quantity of "green-earth” which accompanies it, and which exists in large masses between the decomposing boulders of the rock, sometimes two or three feet in diameter, and at others diminishing to the breadth of the smallest vein. It is frequently too, of stony hardness, so that sometimes it appears to be an original formation rather than the result of decomposition of the porphyritic masses which it separates. The colour is very fine in some places, and from thence it is removed by the natives for a pigment. When put in water, it crumbles and breaks down after the manner of clay. There is also a red clay, intercalated between layers of the trap a little above the great earth-work, which appears to be merely the same kind of material, with the oxide of iron of a red instead of a green colour; this transition, in colour, of "green-earth" being very common.

Just below the "Reversing Station," (1,631 ft.) which is near the top of the Ghauts, I also observed a bed of this porphyritic rock. I did not see any great difference between the basalt at the extreme top of the Ghauts and that immediately beneath; perhaps it was a little blacker, more compact, and less amygdaloidal, but I saw no distinct bed of "overlying basalt" the surface rock passed into the rock beneath without any line of demarcation that I could discover; but more extended observation than I had time to make is here required, to determine satisfactorily the exact characters of the last layer of trap upwards.

Although the amygdaloid trap is for the most part of a blue colour, still some beds are more or less red, brown or black. It is the greater hardness of some beds than others too, which, after becoming weather