well-defined strata, rather appearing like amorphous projecting masses, unless when impure, and then the strata are as well marked as those of the better defined schists. In two instances, the dip was observed N. E., inclination 20°, and N. N. E., inclination 32°. The first of these was a purple arenaceous rock, containing a good deal of carbonate of lime, the second was an almost pure compact dolomite of a light grey, and remarkable for its conchoidal fracture, toughness, and hardness.

255. In the descent to the bed of the Ramgunga, chloritic schist of a perfectly pure type occurs, being in fact green talc slate; it contains metallic copper disseminated, but no attempt has been made to work it. In the bed of the river a schist occurs, which may well be called talcose schist, being a mixture of quartz and talc. It bears the same relation to talc, (prismatic tale mica,) as rhombohedral talc mica. It is in this particular place schistose, and distinctly stratified; but in other quarters, it passes into a massive rock, bearing the same relation to it, which ordinary quartz rock bears to the above schist. It is in fact a talcose quartz rock, as we may call the ordinary type micaceous quartz rock. The titles talcose and micaceous schist might be confined to the schistose types of this compound rock, and that of talcose slate, to the slate composed entirely of indurated talc. This would introduce some precision into our account of rocks. In like manner, chloritic slate should be reserved for the pure mineral, and chloritic schist for the compound types. Without a reform, terminology will never make any real progress.

256. From the bed of the Ramgunga, the route ascends to Gungolee Hath, on the valley of that river from that of the Surjoo. The talcose schist passes into a quartz rock in which the talc is gradually lost, until it at length very closely resembles a sandstone in appearance, argillaceous schist then establishes itself, but whether by transition or per saltum, the state of the surface does not admit of deciding. The dip was observed to be N. 7° E., inclination 45°. Towards the summit of the ridge, magnesian and siliceous limestones begin to prevail, and the crest is entirely composed of a flesh-coloured dolomite, with purple clouded delineations, which I think would form a very handsome material for various ornamental works, as it takes a very high polish, and is not more difficult to cut than ordinary marble. It is traversed by veins of a purplish brown calcareous spar with curved

cleavage, and so strong a pearly lustre, as to be at first mistaken for dolomite spar, (macrotypous lime haloide,) but its specific gravity and ready effervescence with acids, shew it to be rhombohedral lime haloide veins of a resinous quartz; bluish, black and white, are also observable.

257. In descending to the Surjoo, a little blue limestone is seen, and one patch very beautifully variegated with yellow veins of carbonate of lime. The prevailing rock, however, is argillaceous schist; a good deal of what might, in following up the distinction, (Art. 246), be called clay slate also prevails, soft and distinguished by its series of colours as well as by its patches of a different colour from that of the ground. At the bridge, the rock dips S. W. In ascending from the river, an impure hornblende rock begins to appear, remarkable for its numerous cleavage places, which render it so difficult to distinguish the lines of the strata. Hornblende and actynolite schist are found, and a white massy rock, which from a cursory examination, I supposed to be a compound of tremolite and quartz, as the three substances, hornblende, actynolite and tremolite really constitute but one species, (hemi-prismatic augite spar,) there is nothing improbable in this opinion. I have to regret in this, as in many other instances, the want of access to the specimens collected, in drawing up this paper, which prevents me from revising particulars of this description, stated hypothetically in my note book.

258. The hornblende schist ceases a little above the village of Neoolagoon, and is succeeded by gneiss, which is of a porphyritic type, containing superadded prismatic nodules of felspar. This mineral in every case appears to be of greater durability than the basis or ground, and the nodules consequently remain projecting after the other has in a measure disintegrated, giving the rock an exceedingly uneven and rugged surface. The dip was observed to be S. W. Near Jagesur, this gneiss is succeeded by micaceous schist, dipping to S. S. W., with an inclination of 60° above Jagesur. On the Pass the dip had changed S. W. This rock continues to Almorah, and presents nothing very worthy of remark along this line. Near Chandeswur, it dips to S. S. E., with an inclination of about 15o. A few miles from this, it contains beds of brown iron ore, (prismatic iron ore,) which are said to furnish a very good metal. The ore contains a little manganese, rolled pieces composed of grains of quartz sand, and octohedral crystals of magnetic iron ore (octohedral iron ore,) are

found scattered about the surface of a hill in the vicinity of this mine, but no trace could be obtained of a deposit in situ. These pieces are all natural magnets, and have two or more poles according to their shape. Under Kaleenath, the schist becomes highly carburetted and soils strongly; some pieces are white, and on the summit of the ridge where the carburetted type entirely prevails, nodules of graphite are found. The dip in this vicinity changes to N. 44° and N. 22° W., the inclination being 45° and 30°. The rock is latterly extremely like a sandstone, and so friable, that no specimen is obtainable.

259. A short line yet remains to complete the details of the schistose band of rocks, previously to entering on the description of the granite beds. It is the route followed in an excursion from Petorahgurh to visit the copper mines. At Seera, argillaceous schist prevails for the first few miles, to which succeed dolomitic rocks of very variable appearance and grain. Occasionally, they are of very loose aggregation, and crumble to pieces in attempting to procure a specimen, occasionally though these latter are chiefly fragments. In the bed of the river they are so hard and tough that the hammer will scarcely make any impression on them. In every case the grain is crystalline, but very various in size, even within the limits of a hand specimen. Clay slate occurs of a deep iron black colour with straight laminæ, very hard and very brittle. It has a kind of iridescent tarnish, sometimes, on the face of cleavage. Near Kinder Besool, the limestone rocks, less decidedly dolomitic, continue mixed irregularly amongst patches of slate.

260. The route now ascends to Dhurmgurh, situated on the ridge which overlooks the Seera valley, carrying clay slate along that line, and then descends to the mines, which are immediately below the Pass. They are situated in a formation, or bed I should rather call it, for the former term is too general, in which indurated talc, (potstone and talc slate of geologists,) and crystalline granular dolomite are irregularly mixed. They must indeed here be considered as the same rock, geologically speaking, for they mutually interfere, and hand specimens may be obtained in which both substances are separately observable as well as in mixture; access is wanting to the junction of this bed with the surrounding slate, so that its exact nature cannot be ascertained, that is to say, whether it be really a bed or vein. The copper ore is most commonly copper pyrites, (pyramidal copper pyrites,) and it is

associated with iron pyrites, (hexahedral iron pyrites.) These minerals, particularly the latter, are often found imbedded in the potstone. Some part of the galleries are cut in the dolomite rock, part in the potstone, as the two rocks are continually interchanging, so that a gallery begun in the former will, after 20 or 30 yards, be found to be in the latter. The copper evidently traverses both rocks, and as far as the miners' accounts can be trusted, is in veins.

261. Till the publication of Professor Moh's system, great confusion existed on the subject of these two mineral species. We have in some of our most approved system-mongers, long and laboured articles, consisting of many pages of description, tending to shew, that massive tale was something different from potstone, and these again from soapstone; yet if we examine their several qualities, we shall find them identical. Professor Mohs, with the judgment which he has shewn throughout his work, at once rejected futile distinctions that were without differences, and has not hesitated to connect, as mere varieties, scaly tale and potstone. The truth of his views, if they required confirmation, would be found every where in these mountains, where an uninterrupted series of gradations may be traced, from the most perfectly amorphous potstone, through talc slate to the scaly mineral, usually considered a distinct species. Previously to the publication of that excellent work I had found so much difficulty in reconciling the contradictory accounts of mineralogists, that I determined to form a collection of the various types of this mineral, and in consequence, had satisfied myself, that there is in reality no difference whatever in essential character amongst the varieties, which hitherto have figured as distinct species. The inaccurate determination of specific gravities by early writers, servilely copied by their successors, has been partly the cause of this and many other of the opprobia of mineralogy. The following determination of this element, obtained from the specimens above alluded to, will serve to shew, how absolutely the same it is in the different varieties, and to confirm the accuracy of the limits fixed by Professor Mohs, viz. 2.7, 2.8. White potstone, (Seera Mine,)..

Black ditto, (Shergarury,)

Greyish ditto, (Seera,)

Yellowish soapstone, (Kuree,)

Do. very steatic, (ditto,)

2.712

2.76

2.76

2.79

2.74

All these had precisely the same degree of hardness.

2.77

2.7765

262. The dolomite has been equally well discriminated, and correctly fixed by the Professor. The accounts of previous writers only serve to confound the student with tenfold perplexity, from which he is only extricated by his clear views, and precise determinations. That they will very much tend to raise the character of a science, which till his book appeared was but empiricism, is obvious. Of their utility to the student I can myself bear witness, and this very mineral, as well as calcareous spar affords many instances. The limits of the latter are fixed at 2.5 and 2.8, of the former at 2.8 and 2.95. The following are some determinations I made :

Grey compact dolomite,

Greyish white dolomite spar,

Yellowish grey ditto,

Dolomite spar large rombohedrals, ..

Compact dolomite, purple,

2.826 Pass, road to Bagsar

above Belowree.

2.850 Goorung.

2.99 Bed of Mahepore.

2.83 Shor Gorung.

2.83 Gungolee Hat,h.

Of these the third only exceeds the limits, and this by so small a quantity, that it is very likely a revision would bring it equally with the others under those limits. The veins of purplish brown calcareous spar, which are found in the Gungolee dolomite, have the external characters of dolomite spar quite perfect; that is to say, pearly lustre, opacity, and curved or ill-defined cleavage. Being also contained within a magnesian rock, I naturally placed it amongst the specimens of dolomite, but in determining its specific gravity as one of the above list, I found it to be only 2.67. A re-examination and the test of acids satisfied me, that it was really calcareous spar. This is one amongst a hundred instances in which external characters alone are found perfectly inefficient to discriminate minerals, nor is there any thing in the history of science more truly surprising than the pertinacity with which mineralogists have hitherto resisted putting their system on the secure basis of numerical determination.

263. Below the mine, very beautiful massive talc of a snowy whiteness occurs, mixed with unequally white crystalline dolomite. The former is, however, intermixed by rents or fissures, preventing the acquisi

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