« السابقةمتابعة »
clay, clay ironstone, and coal, which consists of four kinds-pitch coal, slate coal, canal coal, and glance coal ; the last however in the secondary series occurs in but small quantity, and is of no value. Resting immediately below the carboniferous or mountain limestone, we find among the Himmalehs a series of slates (the old red sandstone where we have as yet examined being wanting) the equivalent of Murchison's Silurian system, between which however there is no line of demarcation from the transition properly so called, viz. the grey wacke, grey wacke slate, clay slate, &c. having the same angle, dip, and direction.
Shortly after leaving the Fir-tree Bungalow, we meet with the slates in general dipping to the N. E., under an angle of upwards of 70°. At Hurreepoor Bungalow we still meet with the same slates, alternating with quartz rock, and as we approach near to Syree, we meet with a series of alternations of grey wacke, grey wacke slate, clay slate, sandstone, and quartz rock. Syree village is built upon clay slate; on ascending the hill which overlooks Syree, we find the slate occurring nearly at right angles, with the usual dip to the N. E., produced by a large mass of quartz rock. In no part of the mountains which have as yet come under our observation, are the effects of the quartz rock on the grand scale more beautifully seen, than in this locality, nor could a finer example in order to study the effects, and at the same time the relations of the latter, be pointed out. On the south side of the village of Calug, which consists of a few native huts, the slate is highly inclined, and much contorted, and dips to the N. under an angle of 75°. Before reaching the village of Badari, which consists of a small bazar, and about twenty or thirty native houses, we again meet with the quartz rock, stratified, and dipping to the N.W. under an angle of 25° Immediately above the village mentioned, close to which a mountain torrent passes, we have a beautiful section of clay slate, upwards of two hundred feet, being exposed dipping to the N. and W. under an angle of 25o.
At the first resting place used by coolies coming from Simla, a small table-shaped hill, distant about two miles from it, there is an immense dyke of basaltic greenstone, cutting through the clay slate, which at the line of junction, and for some distance, is much indurated. Cutting through the basaltic greenstone we have small dykes of syenitic greenstone, we have therefore here three different ages of formation. From this place to Simla we meet with the same clay slate, in many places however highly crystalline and passing into mica slate. The numerous metamorphisms which the slate assumes around Simla, passing from the rather earthy looking slate
of the transition series, into the highly crystalline slate, which is
1 Grey wacke,
7 Syenite, on both sides of Simla valley, whose direction proceeding down. wards is at first nearly due east and west, it then takes a turn to the south west ; there is clay slate ; on its east and by north side we have the Jacko mountain, reaching to a height of 8,300 feet above the level of the sea. It is entirely composed of clay slate, in many places as near; and at the summit, we meet with large embedded dykes of quartz rock.+ The ridge upon which the Simla bazar
* Journ. on the Geology of the Criffel Kirkbran and the Needle's Eye in Galloway. Wern. Tran. vol. IV. Dr. Grierson on the mica of Galloway. Ibid, vol. II. and Hay Cunningham, locis citatis.
† The Jacko is the highest mountain met with in the neighbourhood of Simla, it is considered to be about 800 feet above the Simla bazar. By experiments made conjointly with Dr. Macleod, with thermometers and boiling water, we ascertained that his house, situated at the foot of Jacko, was 7,800. By similar experiments we ascertained the height of Subathoo 4,480 (Mr. G. Clerk's house at Bunnassur 5,600); on all occasions we used rain water if it (or snow water which is the best) is not used, the result given is usually inaccurate, common spring water containing a quantity of foreign ingredients, it ought therefore never; if possible, be had recourse to.
rests is also almost entirely composed of clay slate, dipping to the south east under an angle of 25°. In Section No. III. we have given a view of the strata extending from Dr. Macleod's house, at the foot of Jacko, immediately above the bazar, to Lord Auckland's Road.
The clay slate varies in colour from bluish black to ash grey, with the various intermediate tints. In structure, it varies from rather earthy to highly crystalline, and in its transitions we have it passing, as in Simla valley, into chlorite slate; in other places, as in the Auckland Road, into quartz rock, the latter of which frequently alternates with it, in thin layers, forming mica slate. In composition, as already stated, it frequently consists of nothing but mica. In the section of the Auckland Road, we meet with a large mass of slaty quartz rock, formed by thin layers of clay slate alternating with the quartz rock; in fact it is almost identically the same in mineralogical characters, as the rock met with in the Lockken district in Kirkcudbright, Scotland; from the first time we examined this section we were instantly struck with the identity, which a further examination fully verified, of the induration and alternation of the clay slate in junction with quartz rock; we have a beautiful example at the first water-fall below Simla. Here there are large masses of quartz, forming dykes of many yards in thickness in the clay slate, whose greyish white colour contrast finely with the dark bluish colour of the latter rock.
The fall is a perpendicular height of about 140 feet, over which, during the rainy season, a very considerable body of water is precipitated, forming an interesting sight, well worthy of the attention of the traveller ; with Dr. Macleod we also visited and examined the other water-fall, some distance below the one mentioned, and found the rocks, &c. to be similar. In tracing the strata in the bed of the river from it towards Simla, we meet with many junctions, and it is here we find the clay slate passing into chlorite slate. The rolled masses, or boulders, principally consist of quartz rock, syenite, clay slate, chlorite slate, &c. In a valley bearing north and by east from Anandale, there is a quarry of clay slate, which is used as a roofing material for many of the houses in Simla, the rouge, huge, thick and unshapely masses employed are quite in unison with the mineralogical operations carried on in other parts of India ; in fact it is quite remarkable that the beams are able to support the enormous weight superimposed. We have already stated that no where in the immediate neighbourhood of Simla is grey wacke to be met with ; but as we proceed north ward towards Kotgur, about one and a half miles, we meet with a series of alternations of grey wacke, grey wacke slate, and clay slate, having the same dip and direction as the slates just mentioned, proving that they must be of the same age, and that they were up-raised contemporaneously. How far this series extends towards the north we have not as yet ascertained ; as far as we have gone, viz. upwards of four miles beyond Simla, we have still found it.* Four miles to the south of Simla we have already noticed a similar series of alternations. In its characters, the grey wacke is characteristic, consisting of a basis of clay slate, with imbedded fragments of clay slate, quartz rock, flints, &c. The size of the embedded fragment varies from upwards of six inches, to so small as to be almost imperceptible to the naked eye, and forming gradually a transition from the grey wacke to the grey wacke slate, and from it into clay slate, in which no fragments exist. In No. V. we have given a section exhibiting the different alternations from the most northern point to which we have as yet gone to Simla. It is rather remarkable, that here, where we find the grey wacke unaltered, quartz rock occurs in but small quantity. The clay slate which alternates with the two rocks mentioned, is identical in its mineralogical characters with the clay slate of Simla, when not in junction with quartz rock.
Quartz rocks occur in three different forms ; as imbedded masses in the slate, as dykes or veins, and in masses exhibiting the regular stratified form; the seams of stratification being as well marked as either those of clay slate, or grey wacke slate. In structure it is compact or granular, much more frequently the former. The colour is generally greyish white; sometimes, owing to the presence of iron, it is reddish brown, blood or brick red ; in a few instances we have observed it of a rose red colour, void, however, of the fine translucency observed
Since the above was written we have in company with Dr. Macleod examined the country as far as Tagoo; the predominant rock is still the clay slate ; near to Mabassoo we meet with two alternations of quartz rocks. In this route the clay slate is frequently formed contorted in a most extraordinary manner. The dip is generally north and west, the angle varying, in some places it was about 70%. The magni. ficence and grandeur of the view of the snowy range from Mabassoo can be better imagined than described, and the optical delusion is so great, as to make it appear not more than six or seven miles distant. In the foreground you have here and there thick wooded districts, whose dark shade contrasts beautifully with the bleak white, but majestic peaks, whose snow-clad summits tower into the heavens, and defy all human exertion to surmount. Here also you see well what we have already stated, though with some doubt, viz. the parallelism of the subordinate mountain ranges and valleys.
in the rose quartz* met with in Bavaria, Saxony, &c. That the quartz rock owes its formation in many places to Plutonian action, is fully proved by the observations already made, and by many other sections not yet noticed. Probably the best to illustrate this, is to be met with on the road leading from the small church of Simla down to the river torrent. Here we have a large dyke of quartz rock, cutting through the slate, and altering it; superimposed there is a large mass of slate lying upon the outcrop of the dyke, unconformable to the other slate, and at the same time converted into a highly crystalline mass, which seems to have been torn off from the subjacent rock at the time when the quartz rock came from below (see section VI.); moreover to meet with large masses of slate imbedded in the quartz rock, is not an uncommon occurrence. In the Simla road, immediately above the cantonments of the Goorka battalion, there is a good example. The alteration, shifts, &c., met with in the clay slate when near the quartz rock (see section VII.), is also another proof of the existence of Plutonian action, and moreover we find it passing imperceptibly in the new road, or Auckland Road, into syenite. Here also imbedded in the quartz rock, we frequently meet with veins of quartz of a much whiter colour, pointing out in a striking manner the shifts which have taken place (see section VIII.) That however in other places it is Neptunian deposition, is evident from its regularly stratified form, and at the same time when in contact, not altering the clay slate.
The last rock we have to notice is Syenite. It occurs in only one locality, in the form of a large amorphous dyke, intersecting and altering the clay slate, it passes gradually into quartz rock. In structure it is small, granular, and is composed of quartz and horn. blende, the former of a greyish white, the latter of a leek green colour. As we have not examined sufficiently minute the trapst mentioned, we shall take another opportunity of giving an account of them.
* The rose quartz of mineralogists, owes its colour to manganese, and is much prized, when pure, as a precious stone; it is however very liable to fade, if much exposed to the air. Jam. Manus, Sect.
† At Rajmahul, where it is stated existed the capital of the Mahomedan power in Bengal, in the reign of Akbar, towards the end of the sixteenth century, we find among the ruins some fine examples exhibiting the polish, which some of the trap are capable of receiving. Thus, in the Sungi Dullau, or marble hall, erroneously so called, there are still existing some enormous slates of beautifully polished basaltic clinkstone, ornamenting the doorways, walls, &c. which by the ignorant have been considered black marble, and thus given rise to the erroneous name. In every work we have consulted, this term is used. It is also stated that the ruins principally consist of granite, a word too frequently used as a cloak for ignorance. What we principally saw were bricks and trap.