Gideon Algernon Mantell

GEOLOGICAL EXCURSION TO MATLOCK.

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------ "In famed Attica such lovely dales
Are rarely seen; nor can fair TempÈ boast
A charm they know not."

Lord Byron.

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The beautiful and romantic Dale of Matlock, although one hundred and forty-two miles distant, is now brought within nine hours of the metropolis. Leaving London from the Euston-square station of the Birmingham Railway, at eleven o’clock (taking the precaution to have a ticket that will ensure a passage from Rugby by the Midland Counties Railroad to Derby), we pass over in succession the clays, sands, and beds of gravel, composing the Tertiary strata of the London basin; and at Watford, steep cuttings of these deposits are seen on each side of the station. A long tunnel through the White Chalk of Hertfordshire is then passed; and at Tring we arrive at the termination of the Chalk, and obtain a fine view of the north-west escarpment of the Downs, which is seen extending on the right towards Ivinghoe, and attaining an elevation of 900 feet. The railway then proceeds over the Chalk-marl, Galt, and Lower Greensand, to near Leighton, where these members of the Cretaceous system are succeeded by the Oolite of Buckinghamshire and Northamptonshire; and the line crosses the Grand Junction Canal near the emergence of the Lias; the Rugby station being situated in the midst of that formation. We then enter the Midland Counties line, and pass on to Stoney Stanton, where the Lias terminates, and the Triassic or New Red strata appear; proceeding towards Leicester, clays and marls of a dull red colour, denoting the Triassic deposits, constitute the slopes on each side the railway. As we approach Leicester, the craggy summits of Charnwood Forest appear in the distance On the left, with here and there an isolated conical hill, indicating the protruded masses of granite, porphyry, and syenite, which belong to the group of plutonic rocks of the central county of England. The granitic mass of Mount Sorel is seen along the railway from Sileby to Barrow, Charnwood Forest appearing in the distance.

Leaving Leicester for Derby, the route continues along Triassic strata; and a good section of the variegated marls, with veins of white fibrous gypsum, may be observed at Red Hill, where a short tunnel perforates a ridge of the same deposits. The railroad then emerges on the verdant alluvial plain through which the Trent, its waters increased by the confluence of the Dove and the Soar, pursues its course towards the north, and joins the Humber at Alkborough, whence the united streams flow on, and empty themselves into the German Ocean.

At Derby, where the train arrives at half-past five, half an hour is allowed for dinner; and we then proceed by the North Midland line, by Duffield and Helper, through a beautiful valley watered by the Derwent, which is seen winding its way towards Derby. The high grounds skirting this valley are composed of the millstone-grit and sandstone of the Carboniferous system (see p. 31). Ten miles beyond Derby, we arrive at Amber Gate station, where an omnibus and other conveyances are in waiting, to convey passengers to Cromford and Matlock.[794]

[794] As it frequently happens that more passengers are brought by the train, than the omnibus or coach can convey, some activity is necessary to secure an outside place, which it is most desirable for the s geological tourist to possess, that he may command a good view of the splendid scenery, which will be constantly opening on his sight, through the romantic pass that leads to Matlock.

The road from Amber Gate leads through a succession of picturesque scenes of surpassing beauty. At Whatstandwell-bridge[795] (see Lign. 273), over which the Derwent is crossed, the view is most imposing. The river is seen rapidly pursuing its course between richly wooded ravines, fringed with luxuriant foliage to the water’s edge.[796] As we advance, the bold mountain ridge of Crich Hill appears on the light, with the village of Holloway at a considerable elevation, and Lea Mills near the base of the range; while on the left are the hills and overhanging woods of Alderwasley. Ascending to the Inn at Cromford, the road turns suddenly to the right, and by an opening cut through a mass of strata twenty feet thick, called Scarthing Rock, conducts to the southern entrance of Matlock Dale. On passing this chasm, the glorious features of this enchanting region burst on the view. On the east is a range of limestone cliffs, richly wooded, with Willersley Castle, the seat of the Arkwrights, embosomed in trees on a commanding eminence; and on the west, a rocky precipice, crested with forests, and its sides partially covered with copses and brushwood; while the river, dashing through the ravine on the right, completes the magic of the picture—

At the distance of about half a mile, we pass the toll-gate, and a bold mural precipice of mountain limestone suddenly appears on the eastern bank of the river; while on the western, a steep slope, clothed with verdure, rises rapidly to the lofty pine-clad eminence called Masson Hill, an elevation of upwards of 1,000 feet. The base of this mountain stretches directly across the dale in front, and apparently presents a barrier to an egress from the valley on the north; but as we advance, the road is seen to wind round its foot by a defile along the left bank of the river; and the magnificent rock called the High Tor rises in majestic grandeur on the right. The valley now gradually expands, and, at the distance of about two and a half miles from the entrance at Scarthing’s rock, terminates in the champaign country beyond Matlock village.[797] From the precipitous nature of the escarpment of mountain limestone which forms the eastern boundary of the dale, the buildings at Matlock Bath are confined to the left or western side of the Derwent, and are scattered here and there among the trees, on the projecting plots and terraces formed by the fallen cliffs of sandstone, which, during the lapse of ages, have become partially disintegrated and are more or less concealed by vegetable soil; the projecting rocks are covered with lichens, mosses, and ferns.

The hotels, of which there are several, are all delightfully situated; but the Temple Hotel, which stands on a terrace on the side of Masson Hill, about a hundred feet above the river, has the preference in my estimation; its elevated situation, its seclusion from the noise and bustle of the village, and its bowers and hedge-rows of sweet-briar and roses, imparting a character of sylvan beauty to the spot, peculiarly grateful to the traveller who wishes to enjoy a quiet sojourn at Matlock Dale. The local guide-books afford the necessary information to direct the visitor to the celebrated picturesque spots of this beautiful region; our immediate object is to point out the most important geological phenomena.[798]

Geological Position of Matlock Dale.—That the reader may clearly comprehend the geological character of the romantic district in which he is now situated, we will briefly enumerate the several formations over which we passed, in our rapid transit from London; by the aid of the geological map, the following description will be easily comprehended.

Our route from the metropolis commenced from the centre of the Tertiary strata, upon which London is situated, and which fills up an extensive depression or basin in the Chalk; we then passed over, or rather (by the tunnel) through the north-west boundary of the Chalk basin, and successively came upon the Portland stone and other beds of the Oolite, and the Lias; the strata of these formations successively rising from beneath each other as we proceeded. In Leicestershire, the beds of the New Red or Triassic formation emerged from under the Lias; and at the Trent Junction the nature of the deposits was concealed by the alluvial plains of the river. Beyond Derby, we entered upon strata of the Carboniferous system, the Millstone grits and sandstones, and finally reached the Mountain limestone and its associated Magnesian limestones, which compose the mountainous district of Derbyshire. The following diagram will serve to illustrate this description.

The immediate vicinity of Matlock is, therefore, a region of Carboniferous limestone and millstone strata, which, as we have previously explained (see p. 31), are of marine origin; and those beds that contain organic remains abound in extinct species of shells and crinoidea. These rocks are also the grand depository of the ores of lead (see Wond. p. 681), calamine, &c., and contain a variety of minerals of great beauty and interest. This district has also been the theatre, in very remote periods, of great physical changes, and the strata have been upheaved and displaced by volcanic action, the solid rocks rent asunder, and beds of mineral substances, rendered fluid by intense heat, have been injected between the layers, and into the fissures of the sedimentary strata; to these revolutions, the present bold and picturesque features of the country are attributable. Here then are phenomena replete with the highest interest; the very beds of lava may still be seen—the rents and fissures caused by their explosive action, and now lined with rich metallic ores and spars, may be examined—and the thermal waters, rising in perpetual fountains from an incalculable depth, testify that the internal fires, the sources of these catastrophes, though latent, are not extinguished.

A Walk to the Incrusting Springs.—The so-called "petrifying springs and wells" of Derbyshire are celebrated throughout England for the incrusted birds’ nests, baskets, &c. which are very generally purchased by visitors, as mementos of a trip into this county. The nature of this deposition of calcareous matter has already been explained (see p. 39; and Wond. p. 75); and, although the objects above mentioned are scarcely worthy of notice, the natural operations by which the tufa and travertine are produced, are extremely interesting.[799]

Our first stroll shall therefore be to the beds of tufa which have been formed in remote ages by this operation and which now constitute the terrace on which the Old Bath and two other hotels, and the elegant modern Church are situated. Proceeding from our Inn, the tufaceous rock may be seen protruding in masses on the right hand, in front of the beautiful parterres of the hotels; and upon crossing the road, where a narrow path leads down to the bed of the river, and nearly opposite to the new church, the lower beds of tufa are exposed in a quarry, from which large blocks of the coarse, porous stone are extracted for grotto and rock-work. From this spot I collected very fine impressions of the foliage of the oak, elm, and hazel, leaves of adder’s tongue (scolopendrium), &c. and large portions of moss, beautifully incrusted.[800]

The origin of this deposit of tufa, which covers so huge an area along the western flank of the mountain range of Masson Hill, is attributable to the thermal springs having, at some very remote period, issued from a much higher source than at present, and flowing down the side of the hill into the river at its foot, the water, as it cooled, deposited the lime with which it was charged on the stems, branches, leaves, and other extraneous bodies. At this time the springs escape from crevices in the rocks at an elevation of about one hundred feet above the bed of the river; the waters, at their source, have a temperature of from 66° to 68°, and contain free carbonic acid and minute quantities of muriates and sulphates of magnesia, lime, and soda. Their origin is now concealed, and the water conducted by pipes to the various baths and fountains; but wherever a rill escapes, and flows down the hill, the moss, &c. is quickly incrusted. I was informed, that in about eight mouths a basket of eggs would be entirely enveloped in a thick mass of tufa. The uniform high temperature of these waters shows that they emanate from a very deep source; and it is probable that they originate from steam, which is cooled and condensed as it approaches the surface of the earth. The miners assured me, that the springs burst out from beneath the volcanic rock, here termed toadstone, and that the water, when it first issues, is of a higher temperature than the Matlock Bath water; but its heat is reduced by the cool land-springs with which it becomes intermingled.

Most waters that flow through limestone districts deposit travertine more or less abundantly; and I observed several streams in my rambles in the neighbourhood of Matlock which appeared to possess this property in as great a degree as the thermal springs. There is a lovely waterfall, which issues from the side of a mountain that flanks the road leading by Via Gellia to Middleton Moor, at an elevation of two hundred feet, and flows into the adjacent valley, bounding and dancing from one mossy knoll to another, and appearing from the opposite hill like a stream of molten silver, undulating through a carpet of emerald green. The waters of this cascade have formed a thick bed of travertine along the side of the hill; and the stone is of so firm a texture, that the walls of a cottage hard by are constructed of it.

I gathered from the banks of this waterfall, bundles of moss and groups of small shells incrusted with a beautiful white tufa; and impressions of leaves, twigs, &c. were observable in the blocks of travertine recently quarried.

In contemplating the effects produced by these limpid streams, by which perishable leaves and fragile shells are preserved for ages in solid masses of rock, we are reminded of the forcible and eloquent remarks of Sir Humphry Davy, when observing similar phenomena in the volcanic regions of Italy. "How marvellous are those laws, by which even the humblest types of organic existence are preserved though born amidst the sources of their destruction; and by which a species of immortality is given to generations, floating, as it were, like evanescent bubbles on a stream raised from the deepest caverns of the earth, and instantly losing what may be called its spirit in the atmosphere!"[801]

Visit to the Cavern of the High Tor.—After the visitor has taken a general view of the romantic scenery around him, a visit to the cavern at the foot of the High Tor will enable him to comprehend the nature of those physical changes which have imparted to this district its picturesque character. Descending into the valley and passing northwards, through the only street in Matlock Bath, along the banks of the Derwent, which are beautifully overshadowed by copses and forest trees, the bold cliff of mountain limestone, called the High Tor, the most imposing feature in the dale, suddenly appears on the right bank of the river. This rock rises to the height of four hundred feet; the upper half forming a bare and nearly perpendicular wall of limestone; the lower portion being concealed by brushwood and luxuriant foliage to the river s edge. At this spot, a rude wooden hand-rail is stretched across the Derwent, which is here of considerable breadth, and dashes along over fallen masses of rock in its course towards the south. The High Tor (Lign. 270) consists of a capping of Drift and of Millstone grit (2); of a series of beds of limestone with encrinites and shells, slightly inclined southward (1); of a layer of volcanic matter, termed in Derbyshire toadstone, from its mottled yellow and greenish appearance (3); and of a bed of Trap, or toadstone (b), at the base, and near the floor at the entrance of the fissure or excavation in the limestone forming the cavern (a); which trap rock also appears on the opposite bank of the river (c), beneath the highly inclined and dislocated masses of limestone, forming part of the base of Masson Hill. The upper bed of toadstone (3) cannot be seen, for the face of the cliff (although represented bare for the sake of perspicuity in the plan, Lign. 270) is entirely concealed, half-way up, by dense foliage; but an intelligent miner assured me that such was the fact, and that, in sinking a shaft in the opposite hill, toadstone was found in a corresponding situation. Upon entering the cavern, which is not of considerable extent, the first phenomenon to be observed is the bed of toadstone, which protrudes near the floor, beneath a stratum of limestone. The limestone in contact with the trap is in some places changed to a light green colour, and has a slaty texture, from the effects of intense heat under great pressure; it is often permeated with veins of pyrites, and white calcareous spar. The inner recesses of the cavern are literally covered, both on the floor and sides, with very large rhomboidal crystals of carbonite of lime, of the form commonly called dog-tooth spar; the cave surpasses, in this respect, every other in Derbyshire.

Within a few hundred yards of the cavern, a gallery has been driven into the cliff, and a vein of lead (galena) discovered, and worked with some success. Tine masses of blue fluor (provincially termed blue John) and double refracting calcareous spar were also obtained. On the opposite bank of the Derwent, beneath the limestone, and extending along the road-side for two or three hundred yards, a bed of toadstone, evidently the continuation of that at the base of the High Tor, is distinctly exposed.

Proceeding northwards, the line of mural precipices, of which the High Tor is the most elevated point, gradually descends; but there is a bold and bare rock, called the Church Tor, from the church of the village of Matlock being situated near its summit, that requires particular remark; for on the face of this cliff the strata present a series of curves, or rather arches, nowhere broken, but having such an appearance as would result from an expansive force from beneath uplifting a group of horizontal strata, while yet in a soft or plastic state. The upper beds of limestone at the Church Tor abound in marine shells (Spirifer, see p. 390, particularly the large species, S. giganteus). Such are the appearances presented by the strata in this locality, on the right bank of the Derwent. On the opposite side of the valley are beds of limestone, many of them varying in mineral constitution from those we have examined, being of a light yellowish dun or cream colour (hence called Dun-stone), and containing magnesia; in these strata traces of fossil plants are occasionally found. These magnesian limestones are of a granular texture and extremely hard; they are said to be very rich in lead and calamine, and have been extensively worked. The prevailing rocks on this (the western) side of the valley belong to this group.

Geological Formations of Derbyshire.—Before we proceed on our walk, let us sit down awhile on this mossy bank, beneath the magnificent knoll of trees that here overshadows the river, and, by a reference to the geological table (p. 31) and the geological map, obtain a clear idea of the nature and succession of the strata around us; in other words, the order of superposition of the deposits of Derbyshire.

1. Lowermost. A bed of compact Basalt or Trap (in Derbyshire called Toadstone), of uncertain thickness and extent. This rock consists of mineral matter that has undergone complete fusion, and been erupted from the profound depths of some internal source of intense heat (see Wond. pp. 684, 848). The upheaving force thus put in action having been unequally exerted in different places, the superincumbent beds of limestone have been protruded in dome-shaped masses through the upper strata; and are now seen bent and curved, forming what is termed arched stratification.[802]

Vesicular or amygdaloidal Toadstone. This partakes more of the character of scoriÆ, being full of little cells or cavities formed by air bubbles; when these cavities are filled with other mineral matter, as is often the case, the rock is termed amygdaloidal. This bed of Trap was formerly considered to be distinct from the lowermost; but it is now supposed, and with much probability, that all the masses of igneous rock that pierce, or are intercalated with, the sedimentary strata, have sprung from one common source, and are but lateral protrusions from some grand mass of erupted materials.[803]

2. Limestones with intervening layers of clay, and Magnesian limestones, or Dunstones.

3. Alternation of Limestone and Shale. Many of these limestones abound in organic remains; and it is in this group that the ornamental marbles of Derbyshire are comprised. The upper beds are generally of a slaty texture, and contain layers and nodules of chert, which often afford exquisite siliceous casts of the stems of Crinoidea (pulley-stones, see p. 284; and Wond. p. 650), and shells; white chert or porcelain-stone, and black jasper or flinty slate also occur in these beds.

4. Millstone Grit and Shale, and coarse sandstones; these form the subsoil of the principal heights of the mountain ranges, their sterile soil supporting only a covering of ling and heath.

5. Coal Measures; consisting of beds of Coal, with intervening layers of shale, clay, and ironstone (see p. 80).

6. Permian and Triassic strata (see pp. 29, 30).

The mineral substances found in the above strata in Derbyshire are very numerous, and the organic remains equally so, and of a highly interesting character.[804]

This enumeration of the geological formations of which the country around Matlock is composed will enable us to proceed on our rambles without further digression, and should the reader be at a loss to comprehend the nature of any of the rocks or strata we may meet with on our way, he can refer to the above description.

Mr. Bakewell, with his wonted penetration, first detected the true character of the stratification of the High Tor, previous writers having described this cliff as being composed of nearly horizontal layers. But this is a deceptive appearance; for, although, when viewed in front, or in the direction of their planes, the strata appear to be horizontal, yet they are in reality highly inclined, as may be seen in the line of dip, and enfold or envelope the back of the cliff; and they are continued into the hill (Masson) on the opposite side of the valley, where they present a similar arrangement. The continuity of the strata is broken by the vale of the Derwent, which has evidently originated in a fissure extending along the axis of elevation, in a direction from north to south; thus forming the water channel for the drainage of the country on the north, and the bed of the present river. We have already pointed out the curved position of the strata on the face of the Church Tor.

Excursion to Crich Hill.—The appearances observable at the High Tor are of so striking a character, and involve the consideration of so many interesting phenomena relating to the physical mutations which this district has undergone, that it is desirable, while they are strongly impressed upon the mind, to take an excursion to Crich, a few miles to the south-east of Matlock. Here there is an entire mountain of limestone, formed by a protrusion of numerous strata, many hundred feet in thickness, through the once superincumbent beds of millstone grit and sandstone, into a dome-shaped mass, upwards of 800 feet high. And there it stands, a stupendous monument of one of the past revolutions of the globe, with its arches of rifted rock, supported by a central mound of erupted mineral matter, now cooled down into an amorphous mass of compact basalt! Were there no other object of interest near Matlock, Crich Hill would alone render it worthy of resort.

From the heights above our hotel, looking towards the south-east, a mountain remarkable for its elevation and obtusely conical configuration, and distinguished by a tower on the summit, forms a striking object on the horizon, at an apparent distance of three or four miles—this is Crich Hill; and on the same range, to the right, is seen the church-spire of Crich village (see Lign. 272).

A long summer’s day is not too long to visit this mountain, and examine all its interesting details. A good pedestrian should proceed with his hammer and haversack, for every step of the road is replete with interest; and as numerous specimens will be obtained, bags, paper, and boxes should be taken. If an invalid or ladies be of the party, it will be desirable to have a carriage for the day, and dine at the little village of Crich;[805] and, if time permit, the interesting ruins of South Wingfield Manor-House (once the prison of Mary of Scotland), about two miles from Crich, may also be visited.

The shortest drive from Matlock to Crich Hill is over Cromford-bridge; but a far more picturesque route is by the Derby-road to Whatstandwell-bridge (see Lign. 273), and from thence ascending the hill to Crich, and returning home by Holloway; making the entire distance about twelve miles. As our immediate object is to examine the geological features of the mountain, we shall proceed by the nearest road; and upon reaching Scarthing Rock, turn to the left, by Wellersley Castle grounds, having on the right a bold escarpment of mountain limestone, with layers of chert in nodules and amorphous masses. At Cromford Canal, the limestone suddenly terminates, and sinks beneath the surrounding alluvial silt of the river valley, and the millstone grit. We will chip off a few specimens of the chert, to examine at leisure. Crossing the bridge, the road winds round the foot of the hills of sandstone, which lie on our left, while on the right is the valley of the Derwent, and the river is seen here and there through openings in the copses and hedge-rows, meandering through the rich meadow-lands of the valley, which are flanked on the west by a magnificent range of lofty hills, clothed with the luxuriant woods of Alderwasley. The character of the scenery from this point of the road, till we ascend the high ground, is faithfully and graphically portrayed by Mr. Rhodes.[806]

"The road lies through a beautiful valley by the side of the Derwent; sloping meadows, crowned high above with a long range of magnificent woods, skirt the road-side on the left: on the right the river, pursuing its winding way beneath the umbrageous branches of oak, ash, alder, hazel, and sycamore, and bubbling as it passes along, is a beautiful object. About two miles below Cromford-bridge, the road leaves the more open part of the valley, and plunges into the thick woods that environ the little hamlet of Lea; a lovely spot, romantically situated by the side of a sparkling stream, in a deep hollow, amongst steep hills covered with foliage, and fields of the freshest verdure. The houses of this secluded village, with the exception of here and there a comfortable cottage, are handsome residences, nestling among orchards and parterres of flowers. Everything was flourishing most luxuriantly; and when we passed through the place, the hollyhocks, dahlias, and roses were in full blossom, and gave an extremely bright and cheerful aspect to the scene. The road continues through Lea Wood to Holloway by a very steep ascent, and from the toll-gate at the top of the hill it traverses the side of a mountainous ridge, covered with wood and intervening rock. The prospect is now magnificent: on the right a scene of great extent opens to the view, rich in all that constitutes the highest beauty in landscape. The summits of the two ranges of hills that form the eastern and western boundaries of the fertile valley at our feet are here from three to four miles apart; and the extent from north to south is from ten to twelve. Many minor eminences, rich with wood and intervening verdure, adorn this enchanting scene, through which the Derwent, sometimes hidden by overhanging trees, and sometimes sparkling with light, flows with busy speed and uninterrupted current by Belper, Milford, and Duffield, to Derby; the whole presenting an assemblage of splendid scenery finely diversified and rich in picturesque beauty. The woods of Alderwasley, that cover the hills from below Whatstandwell-bridge, to the dark pine-crowned eminence of Stonnis, are peculiarly imposing and magnificent."

Near the village of Holloway there are several quarries opened on the side of the hill, which enable us to ascertain that this range is composed of strata of millstone grit and sandstone, highly inclined and dipping from the hill. The beds are so split and shattered in every direction, that no large blocks can be procured, and the stone, although a good building material, is therefore only employed in the construction of the cottages and houses in the immediate vicinity. The vignette of this volume represents a mass of the inclined sandstone strata near this place. The reader will recollect that the hills on the opposite side of the valley, on our right, are also composed of similar strata; and that the ridge, covered with fir-trees, marks the bold escarpment of the millstone grit at Stonnis, over Cromford; so that the geological horizon of the valley, as seen from this spot, is wholly formed by the millstone grits and sandstones. A mile beyond Holloway toll-gate, the road turns to the left, and the bare dome of mountain limestone of Crich Hill is before us. We soon arrive at a limestone quarry, in which the strata are seen to be distinctly arched (see Lign. 271, p. 886), as in the cliff at Matlock Church Tor.

We will alight here to examine the rock more closely, and obtain specimens. Here we see that the strata are inclined both to the right and to the left, and also lean towards the central axis of the hill in front of us; presenting such an appearance as would be afforded by an excavation made in an onion, or other spheroidal body, formed of a series of concentric layers. The limestone in this quarry is of the usual subcrystalline character, abounding in shells, principally Spirifer. There are numerous vertical and oblique fissures in the rock, and these are more or less incrusted with minerals and spars, which have evidently been deposited by electro-chemical action, and admirably exemplify the manner in which the rich veins of lead, &c. are distributed in the strata of the interior of the mountain. In a crevice of the rock, in which the mineral contents were undisturbed, the arrangement of the prevailing minerals of this part of Derbyshire, namely, galena (sulphuret of lead), sulphate of barytes (here termed cawk), and fluor spar, was beautifully displayed. A layer of the blue sulphuret of lead, or galena, was spread over the surface of limestone forming the walls of the fissure: upon this was a thick stratum of white sulphate of barytes; and on the latter, fluor spar, of a light blue colour, forming cubic crystals on the surface nearest the cavity of the fissure, which therefore appeared to be lined with crystals of fluor.[807]

About half a mile beyond, we arrive at Wakebridge, near which there are several very productive lead mines. The "Glory-mine," one of the richest in Derbyshire, is said, some ten years since, to have been worth from thirty to forty thousand pounds a-year.[808] A mining establishment, on the left hand, where a powerful steam-engine is constantly at work, affords numerous specimens of the usual I Derbyshire spars and minerals; and from among the heaps of refuse thrown by the visitor may make an interesting collection. Near this spot, a vertical shaft was sunk in the side of the hill, in search for lead ore, and at the depth of twenty fathoms, a rock of compact Trap was reached; the work was continued for a few yards deeper, but ultimately abandoned as fruitless. A gallery was subsequently driven into the side of the hill, lower down, and here, too, the trap was found; thus proving the existence of a central protrusion of igneous rock, over which the bent strata of mountain limestone are now disposed in consecutive layers. Numerous blocks of this compact trap or basalt, some of which are veined with red jasper, lie scattered about the site of the old shaft, and an interesting suite of specimens may be collected. Pursuing our way, the limestone strata are seen in openings on the hill side, having the same remarkable arrangement as those before described.

Upon arriving where the road divides,[809] we must proceed on foot and visit the quarries, and examine the exposed masses of rock, that we may clearly comprehend the structure of the mountain. We will now ascend by the pathway that leads to the summit, and on the left several good sections of the strata are displayed. On reaching the tower on the crest of the mountain (Lign. 272, p. 887), a magnificent panorama bursts upon our sight; but which no language can adequately describe. Here and there bare pinnacles of rifted rock protrude through the green sward; and masses of white, yellowish, and pink sulphate of barytes, pyrites, fluor, and other minerals lie strewn upon the surface.[810]

Having reposed for some time at the foot of the tower to enjoy the glorious prospect spread around us, correct our notes, look over, trim, and wrap up our specimens, we will now descend to the north-eastern side of the hill, that the appearance of the strata on that aspect may also be examined. But ere we leave the summit, again let me call your attention to its external configuration. Were it not on too extended a scale, we might suppose that we were standing on an ancient earth-work, or encampment, formed of limestone, surrounded by a deep fosse or ditch, and flanked by precipitous embankments of millstone grit and sandstone, so strongly defined are the physical features of this remarkable mountain.

We will now visit a large quarry on the eastern side, which presents a fine section of the limestone strata, above 100 feet thick (see Lign. 271), and which, like those we have previously observed, are disposed in curves, and enfold, as it were, the central axis of the hill; and the rock is shivered and fissured in every direction. A thick bed of drift, or alluvial debris, covers the limestone strata, as shown in Lign. 271; and in it, partially rolled blocks of sandstone, some of them of great size, are imbedded. The direction of the dip of the strata in this quarry is indicated by the arrows.

Let us now take a retrospect of the facts investigate during this morning’s ramble, and consider how far Mr. Bakewell’s interpretation of these phenomena (see p. 879) is in accordance with the data we have obtained. The outline of Crich Hill, as seen from a moderate distance, is that of an insulated oblong dome, encircled by precipitous escarpments, or angular eminences of less elevation. The annexed sketch (Lign. 272), by my friend, Henry Carr, Esq. C.E., of Duffield, to whom I am also indebted for a survey of Crich Hill, and admeasurements of the dip of the strata, will render this feature in the physical geography of the country more apparent.

In Lign. 272, the protruded elongated cone of mountain limestone is denoted by the tower, or Stand, on the summit; and the other heights, and the foreground, are composed of millstone grit and sandstone. The highest point of limestone is 716 feet above the level of the Derwent in the adjacent valley; and was estimated by Mr. Bakewell at about 900 feet above the level of the sea. The hill of sandstone on the right, on which the mill stands, is 402 feet high, and conceals Crich village in this view; that in the middle distance, on the left, marked a, is 400 feet high.

This disposition of the millstone escarpments around the central cone of elevated limestone is shown more in detail in the ground-plan, Lign. 273.

Thus we perceive that the strata of mountain-limestone dip from the centre of the hill in every direction, as indicated by the arrows, at various angles, from 20° to 50°; and those of the sandstone hills, which form an irregular zone around Crich, are also highly inclined, and in like manner dip from the central axis, as is shown by the direction of the arrows. Now we know, by observations made in places where the relative position of the Millstone and Limestone has suffered no disturbance, that these two series of strata were originally disposed horizontally and conformably upon each other, thus—

The area, enclosed within a line, and marked Stand, Crich Hill, is the elevated oblong dome of limestone. All the surrounding country is composed of millstone grit and sandstone.

The arrows on the boundary line of Crich Hill denote the direction of the dip of the limestone strata in nine positions measured and determined by Mr. Carr. The dip vanes from 20 to 50, the greatest inclination is on the south-east of the tower.

The arrows on the surrounding millstone escarpments mark the dip of those strata in a sufficient number of stations, to convey a general idea of the position of the mountain masses environing Crich Hill.[811]