ghats of which the Neilgherries are the southern termination, happened at a period long anterior to the existence of life on our planet.

It is for this reason that I think HUMBOLDT's opinion not supported by facts, when he says, "the chain of the Ural, the Baloor tâg, the ghats of the Malabar Coast, and the Vringckan are probably more modern than the "Chains of the Himalaya, and the Teenckan*. We know, that in the Himalaya, at several thousand feet elevation, and on the declivities of the highest ridges themselves, organic remains have been found in limestone, which seems of the age of the carboniferous group.

The nummulitic limestone of Chira Punjí, and the conglomerate rock, which forms the Deria Dún at the foot of the Himalaya, appear to assimilate those mountains to the Alpst. Therefore the Himalaya must have been heaved up at a period posterior to that when the Western ghats were elevated: these last containing not a trace of organic remains in the rocks which form them, while the former abound in them.

ELIE DE BEAUMONT admits the greater antiquity of the Malabar ghats over the Himalaya chain; but he conjectures, by the direction of the ghats being parallel to the Pyrenese-Appenin system, that they may probably belong to his sixth revolution of the surface of the globe. The passage, in which he expresses this perplexity, is worth transcribing, to show of what importance it is to establish the association, and the geological position of the laterite.

"Vouloir suivre ce système jusque dans l' Inde paraitrait peut-être abuser de la faculté des rapprochemens: cependant je crois devoir faire remarquer que la chaine des gâtes sur la côte du Malabar semble se cohordonner à la direction, dont je m' occupe. La grande faille, à laquelle parait dû l'escarpement occidental des gâtes, en élevant le plateau du pays des Maharattes, du Deccan, du Carnatic a élevé du même tems, le grand depôt argille-ferrugineux de laterite, qui forme les points plus élévés de ce plateau, ainsi que le montre la coupe des gâtes donnée par M. CHRISTIE. Il est à regretter que ce depôt de laterite, qui couvre dans l' Inde de si vastes étendues, n'aie, jusqu'a present, offert aucun fossile, et ne puisse être rapporté avec certitude à aucun étage geologique déterminé: mais on peut toujours remarquer que

* Edinburgh Philosophical Journal, October to January, 1832, HUMBOLDT on the Mountain Chains-Volcanos of Central Asia.

A writer in the Bulletin des Sciences Naturelles, concludes that the Dehra Dun is analogous in formation to the Molasse of the Alps; and Doctor FALCONER is of the same opinion.-DE LA BECHE, Geological Manual.

tant qu'on n'aura pas indiqué d'autre chaine* qui produisse sur la laterite l'effet mentionné cidessus, tout conduit à voir dans les gâtes la chaine la plus récente de la presqu'île occidentale de l'Inde, dont elle est en meme tems le trait geometrique le plus prononcé!”

Then he says in a note, that the Himálaya are more recent than the ghats, and the Andes more recent than the Allaghanys of America.

We see, by what BEAUMONT says, that he suspects the laterite to be the equivalent of those rocks deposited during the period that intervened between the deposition of the chalk, and the tertiary beds. But fossil remains being the only sure guide in determining the ages of these formations, and none hitherto having been found in the laterite, the question must still remain sub judice. Besides, we must remark here en passant, that the rocks of that epoch in Europe are all stratified, which is not the case with the laterite.

Before concluding this sketch of the geology of the Neilgherries, we must not pass unnoticed the fact of the absence of all sorts of calcareous formation. Even the widely spread kankar is not met with on the Neilgherries, although we find this travertinic deposit at the very foot of those hills, near Mútúpolium (No. 54).

The total absence of stratified rocks, and of calcareous formations, in this group, seems an additional proof of the remote period of its elevation. The only stratified rock, which appears to have been deposited near the place, through which this plateau was heaved up, is the hornblende slate, which is seen both on the east and on the west sides of the hills, being highly inclined, and having an opposite dip: the group serving as the centre of this anticlinal line.

On looking at the map, we see how the numerous valleys and ravines have a different, and often an opposite, direction. Except three or four of them, which diverge in opposite directions from a central point (Dodabetta), the others are so irregular, that it is impossible to refer them to one and the same cause. They certainly do not belong to the class of valleys of denudation, much less to that of corrosion by the streams: the volume of their waters being so very insignificant and divested of pebbly or sandy detritus, which so much hastens the corrosion of the rock, through which the rivers pass. They probably are the original consequence of the elevating force, which either irre

* "With regard to this part of this passage, to show that there are other chains, having different direction from the Malabar ghats, on the summits of which we see the laterite as an overlying rock, we may quote some of the branches of the Vindiya range, where the laterite overlays either basalt or sandstone; and also many sandstone hills on the Northern Circars : and yet the Vindiya Chain has a different direction from the Malabar ghats.

gularly applied to the different points of the area, or the mass itself, yielding irregularly in the different situations, gave rise to the inequality of the whole surface of these hills.

To conclude, therefore, it seems that the granitic rocks, which occupy the highest hills of this group, forced their way, and were heaved up through the hornblende slate, which was in consequence distorted and lifted up, as it is seen in the outskirts of the plateau, and in some of the low situations among the hills themselves, (the valley S. and close to Kotagherry ;) we must also conclude, that the decomposition of the rock forming the red earth, and the detritus, must have happened at a period anterior to the existence of organic bodies; no remains of which have hitherto been found in them.

Specimens from the Northern Circars.

The specimens (from No. II. to No. IX,) are from the hillock near Puddapungalí; a place not far from Yornagorium, and about five miles from, and south of, Rajahmundry.

After traversing the alluvial plains of Ellore, the road passes near a knoll, the rocks of which are very interesting in a geological point. of view.

Before reaching the foot of the little knoll in the plain, and in the nullahs, are seen numerous pieces and blocks of a hard whitish limestone, spotted in many places with numerous small black specks. This limestone is compact, the fracture glimmering on account of the many grains of calcspar which enter into its composition.

In the deep nullahs, in the plain, and at the foot of the hillock along the road, we see a conglomerate sandstone, which appears to be the lowest visible rock in this place. Ascending the gentle slope of the knoll, we come upon many masses of wacke, which is decom. posing in thick concentric layers. Proceeding a little higher we meet with a thick bed of limestone, similar to the pieces scattered about on the plain.

This limestone abounds with fossil shells, which are clearly and better defined in the upper than in the lower portion of it, where the rock assumes a tufaceous consistence, friable, and almost approaching the appearance of tertiary limestone. The shells are very numerous in this upper stratum; almost the whole rock results from their assemblage; they appear to be chiefly bivalves, with a few univalves. Many of the shells have disappeared, their impressions only remaining; but the oysters which abound in this stratum are in excellent preservation, and easily characterized.

This stratum of limestone, the basset of which is only visible in

the slope of the hillock, has a W. and E. direction. It is overlaid by a thick mass of basalt, which caps the whole hillock. In some places, where this basalt lies immediately over the wacke, this last is converted into jasper. Huge masses of basalt are strewed on the top of the knoll, which forms a kind of table-land extending eastward some of these blocks in their upper surface assume an amygdaloid structure, the cavities being filled with calcspar.

:

I could not in that locality see whether the lower compact limestone was or was not stratified. The more superficial and loose blocks, scattered about on the soil, had no appearance of stratification.

Judging from the appearance of the whole of those hillocks which stretch from N. W. to S. E. in the neighbourhood, they seem to have the same geological features as the one just described. Indeed, my friend Colonel CULLEN, with whom I was examining this knoll, told me, that in some of the neighbouring hills, the position of the limestone and of the basalt is seen more clearly, on account of the abruptness of some of their sides, and the deep ravines which intersect them in every direction, so shewing the order of superposition in the four rocks; which is the following: conglomerate red sandstone supporting the wacke, overlaid by limestone, which is covered by basalt*.

The specimens marked X. and XI. are from the diamond mines at Mallavelly, near Ellore; they appear similar to the alluvial detritus in other localities in India, where this gem is found. The kankar accompanies the deposit in the same way as every where else.

No. XX. is the gneiss of which the hillock near the village of Carvera, close to Púndy, is found. In it the Cleavelandite replaces the laminar felspar, and is seen not only disseminated through the substance of the rock, but forming small strata by itself in long acicular crystalst. It is associated, in this rock, with a prodigious number of amorphous garnets, of which some of the strata appear entirely formed.

The porphyry, No. XII., is from the hills which form the northern boundary of the Garabunda pass, going from Kimidy, Garabunda, Cassibogah, to Púndy.

The hills to the south, and close to the pass itself, are sienitic granite, (No. XXXIII. ;) while those beyond the porphyric hills to the N., towards the high hill of Mehendry, seem to be formed of that

*The trap near Sagur, described by Captain FRANKLIN, appears to have the same association of rocks as the one of which I send specimens.-Asiatic Researches, vol. xviii. Geology of a portion of Bundelkhand, &c., page 30.

† Is this the Pindyray of the Telingas, mentioned by Doctor HEYNE in his Tracts, page 283?

variety of gneiss abounding with albite, the continuation of which is seen N. and near Pundy.

These porphyric hills, therefore, may be considered as the out-goings of an enormous dyke of porphyry, which burst through the hills, having the same direction with them, that is N. E. to S. W.; their appearance is that of huge masses of a black looking unstratified rock; in many places completely divested of any sort of vegetation, particularly in those hillocks, which like the one called Chittakúnda, risę in abrupt, vertical cliffs, which seen within a moderate distance might be taken for basaltic rock.

The porphyry exfoliates in thick concentric laminæ, the more depending portions of which falling off, leave the upper in immense tabular masses, or cubic blocks, perched on the upper part, and sometimes on the declivity of the hill: this porphyry has a good deal of hornblende in its composition, sometimes so much, as to become hornblende prophyry.

In more than one of these masses of porphyry, I remarked thick veins or nests of a granitic rock, or rather gneiss, with pieces of sienitic granite imbedded in it. The crystals of felspar in this porphyry are well defined, many of them two or three inches long, and of a foliated structure. This porphyry seems, as I have said, to extend as far as near the sea-shore at Pundy. Some huge masses of it are seen jutting through the soil about a mile north of the village of Carvera, flanked by the gneiss containing ablite and garnets.

I have put up many specimens of laterite from different localities, by which may be clearly perceived the distinction between the original rock and the conglomerate bearing the same name; but which evidently arises from the conglutination of the detritus of the former. This appears to be the case with the laterite in some places of the plains of the Carnatic.

The specimens (No. XXIII. to XXVI.) are from the hillocks, on which the fort of Puddayaram (near Samalcottah) is built. The position of the visible rocks in this place is the following: the ferruginous sandstone is the lowermost, and has a great degree of compactness, so as to fit it for architectural purposes, in which it seems to be largely employed. It is evidently stratified, the strata being nearly horizontal; the quartz particles are agglutinated by a ferruginous cement,

The sandstone, nearly in the whole extent of the hillock, supports a lithomarge of a whitish or flesh colour, sometimes having a bluish tint. The stratum of this earth is not very thick, and in many places, it is overlaid by a purple-red, compact, slaty hæmatitic iron ore,