Chapter VIII: Introduction: Of the Mount's Bay, and the Land's End District (6)

[94] We must refer the reader to a Paper, "On the Veins of Cornwall," by _W. Phillips, Esq._, published in the 2nd vol. of the Transactions of the London Geological Society; and also to a Paper, "On the relative Age of Veins," by _Joseph Carne, Esq._ in the 2nd vol. of the Cornish Transactions.

[95] We shall pass over, as being too absurd to require any serious refutation, the former belief in the power of the _Virgula Divinatoria_ to discover Lodes. A power less poetical but not less fabulous then the story of the _Virga Fatalis_ that conducted Æneas to the Shades.

[96] _Grass_ is the technical name for the surface on all occasions.

[97] The great Copper Mine, called _Crennis_, was discovered by some casual observers in the cliff.

[98] From _Aditus_, a passage?

[99] The application of this machine in the county is estimated as saving the labour of 10,000 men; whilst the powers of the different steam-engines are considered as at least equivalent to 40,000 more.

[100] See Dr. Forbes's Paper "On the Temperature of Mines," in the second volume of the Transactions of the Cornish Society.

[101] The annual cost of gunpowder, used in the mines of the county, amounts to more than thirty thousand pounds.

[102] Transactions of the Royal Geological Society of Cornwall, vol. 2, page 162.

[103] The quantity of water discharged by the pumps from many of the Cornish mines is very considerable; thus _Huel Abraham_ discharges from the depth of 1440 feet, about 2,092,320 gallons every 24 hours; _Dolcoath_, from nearly the same depth, 535,173 gallons in the same time; and _Huel Vor_, from the depth of 950 feet, 1,692,660 gallons.

[104] See Dr. Forbes's paper on the temperature of mines, in the Transactions of the Royal Geological Society of Cornwall, vol. 2, p. 208; also on the temperature of mines, by R. W. Fox, Esq. ibid. p. 14, and a paper on the same subject by M. P. Moyle, Esq. p. 404.

[105] Crennis Copper Mine returned a clear profit to the adventurers of £84,000 in one year; and Huel Alfred, during the last period of its working, yielded very nearly £130,000, after having defrayed every necessary expense. The adventurers in Huel Vor have lately gained £10,000 in three months. But, on the contrary, how numerous are the losses, not perhaps corresponding in magnitude, in any individual mine, to the gains which have been above stated. In North Downs as much as £90,000 were lost, but this is a rare instance.

[106] The consumption of such articles in a great mine far exceeds any estimate which a person unacquainted with mining operations could possibly imagine. In _Huel Vor_, no less than Three thousand pounds of candles are consumed in a month, and about Three thousand five hundred pounds of Gunpowder.

[107] Before the invention of the _Stamping Mill_, the Tin was pulverised in a kind of mortar, called a _Crazing Mill_; one of which ancient machines is still in the possession of Mr. Williams of Scorrier House.

[108] This process might be more generally employed in Cornwall with much advantage. The green coloured water which so frequently issues from the adits, might be made to yield a considerable portion of Copper, if it were properly received in pits, and submitted to the action of Iron.

[109] Stream Tin, on account of its purity, is alone capable of furnishing the _grain tin_, employed principally by dyers.

[110] The principal Stream works are in the parishes of Lanlivery, Luxilian, St. Blazy, St. Austel, St. Mewan, St. Stephens, and St. Columb. The greatest Stream work in the county is at Carnon, about half-way between Truro and Penrhyn; but there is scarcely a valley in which the operation has not been conducted on a small scale.

[111] In the Ordnance Map of Cornwall, a spot marked "THE GOLD MINE" is noticed, near Liskeard. This name serves only to commemorate one of the many ruinous speculations into which the inhabitants of this County have repeatedly fallen, from a want of mineralogical knowledge. A mass of Pyrites having been discovered in this place, its brilliancy induced a belief that it was GOLD, in consequence of which workings were immediately commenced, and the sanguine adventurers, urged forward no doubt by those who derived an interest from the undertaking, could not be convinced of their error, until the complete ruin of their fortunes obliged them to abandon every hope.

[112] This is the deepest _Adit_ in the country; its mouth or extremity being nearly on a level with the water in one of the creeks of Falmouth Harbour, into which it empties itself. Taking into calculation its various windings, through the numerous mines which it relieves of water, it may be said to be not less than twenty-four miles in length.

[113] Menabilly is situated about four miles west of Fowey, on an eminence at a short distance from the sea.

[114] We have been told that this has been arranged by Mr. Aikin, according to the different modifications of its crystalline form, as they are described by Mr. William Phillips in his elaborate paper published in the 2nd Vol. of the Transactions of the London Geological Society.

[115] See an interesting account of this mineral in a notice entitled "Contributions towards a knowledge of the Geological History of Wood-Tin, by A. Majendie, Esq." in the first volume of the Transactions of the Royal Geological Society of Cornwall.

[116] Since the first edition of this work was printed, the mineral has been found at _Saint Michael's Mount_, and, by Dr. Boase, amongst a pile of ore which was supposed to come from _Botallack_.

[117] In one of which is to be seen the _Muriate of Tin_, as first noticed by the late Reverend William Gregor.

[118] The following are the names of the respectable dealers to whom we recommend the mineralogist to apply,--At _Truro_, Tregoning, Mudge, and Heard;--at _Redruth_, Bennett; at _Gwenap_, Michell;--at _Saint Agnes_, Argall;--at _Falmouth_, Trathan;--and at _Penzance_, Jacobs, the latter of whom has generally a great variety of Saint Just minerals on sale.

[119] OPIE was a parish apprentice to a person of the name of Wheeler, a house carpenter, in the village of Saint Agnes; Dr. Walcott, better known by his poetical appellation of _Peter Pindar_, having been struck, during his occasional visits to the village, by some rude sketches in chalk which were shewn him as the productions of this poor lad, invited him to his house at _Truro_, supplied him with the necessary materials, and enabled him to set up as an itinerant portrait painter, from which station he rose to be Professor of Painting to the Royal Academy.

[120] A highly interesting paper "On the decomposition of the Granite Tors of Cornwall," by this geologist, is published in the second volume of the Transactions of the Geological Society of London.

[121] This may be distinctly seen in the granitic rocks in the islands of Scilly; and in the _Gritstone_ in the park of the late Sir Joseph Banks, in the parish of Ashover in Derbyshire.

[122] The only chemical difference between _Cleavelandite_ and _Felspar_ is, that about 12 per cent. of Potass in the latter is replaced by an equal quantity of Soda in the former. The earthy ingredients in both minerals are the same, and exist in similar proportions. The primary form of each is a doubly oblique prism, but the two prisms differ so essentially from each other in the measurement of their angles, that the substances are easily distinguished from each other by the Goniometer.

EXCURSION VI.

TO KYNANCE COVE, AND THE LIZARD POINT.

An excursion to the peninsula of the Lizard offers to the scientific traveller many objects of great geological interest; he will be enabled to examine a very rare and important series of Rock Formations, while their various gradations and transitions into each other will afford ample materials for speculation. In the course of this excursion it will be our duty to point out some of the more prominent features as they may occur in our progress; but in performing this duty we wish to be considered as merely presenting the geologist with a rough and imperfect outline, which may give a useful direction to his researches, and enable him to acquire, through the medium of his own observation, more ample and perfect information.[123]

To the country south of a line drawn from the mouth of the Helford river, on the east, to the Loe-Bar on the west, has the appellation of the "_Lizard District_" been exclusively applied by Mr. Majendie; and the division appears to have been conventionally received by all the geologists who have traced his steps.

The fundamental rock of this peninsula appears to be _Clay-slate_, associated with _Greywacké_, upon which are successively deposited _Greenstone_, _Diallage rock_, and _Serpentine_. At Marazion several alternate beds of _Slate_ and _Greenstone_ may be observed; the latter of which contains _Asbestus-Actynolite_, and is universally traversed by veins of _Axinite_,[124] which occurs both in an amorphous and crystalline form.

In the vicinity of a projecting ledge of rocks, known by the name of _Cuddan Point_, stands a mansion called _Acton Castle_, which was erected as a marine residence by the late John Stackhouse, Esq. and is at present occupied by Capt. Praed. Its situation is wild and unsheltered, but it commands a prospect of very extraordinary grandeur and beauty.

About four miles from Marazion, and half a mile from the high road towards the coast, are the remains of a building called _Pengerswick Castle_, a square stone tower, with a smaller one annexed, and some ruins of walls, are all that remain of this ancient edifice, but its machiolated gate and embattled turrets are still preserved to announce its military origin. The different rooms are now converted into granaries, but the oak wainscot, which is curiously carved and painted, remains in a tolerable state of preservation. On one of these panels, under a rude representation of water dropping from a rock, with the title "_Perseverance_," is the following poetical inscription.

"What thing is harder than a rock?
What softer is than water clear?
Yet will the same with often drop
The hard rock pierce, which doth appear,
Even so there's nothing so hard to attayne
But may be had with labour and pain."

The classical reader will at once recognise in this inscription a paraphrase of the well known lines of Ovid:

"Quid magis est saxo durum,--Quid mollius unda?
Dura tamen molli Saxa cavantur Aqua."

There exists a tradition that this place belonged in the reign of Henry VIII. to one Milliton, who having slain a man privately, purchased the castle in the name of his son, and immured himself in a secret chamber in the tower.

On a bold pile of _Granite rocks_ which projects from the shore near Pengerswick, Dr. Maton observed clusters of _Trochus crassus_, besides some species of _Actinia_ and _Asterias_, not common on other parts of the coast. Pursuing our route we pass through a country principally composed of Slate, the great Granite chain running to the left of the road, and constituting _Tregoning_, _Godolphin_, and _Breage hills_. The Signal house at the top of _Tregoning hill_, which is 584 feet above the sea, constitutes the most elevated point in the country, and from which both channels are visible. The granite of this hill bears in some parts all the appearance of a stratified rock.

Upon arriving at the village of _Breage_, three miles west of Helston, the traveller should turn off from the high road, in order to visit the Tin Mine called _Huel Vor_, and which lies about a mile and a half to the north-east, and is by far the largest as well as the richest Tin Mine ever worked in Cornwall. Here there are five large Steam Engines for drawing the water out of the mine, besides several others for raising the ore. There are also four large Stamping Mills, worked by Steam, which constitute by far the most interesting part of the machinery. It is not many years since steam was first applied as the moving power of these mills, but without its aid it would have been impossible to stamp the whole of _Huel Vor_ Tin with sufficient expedition. In this mine all the operations are carried on which have been already described in our excursion to Redruth, and the Mining Districts. The ore is also roasted and smelted on the spot. Here then the stranger may witness the whole process, from the period when the ore is broken in the vein, to that when the pure Tin runs out of the furnace, and is laded into moulds which contain about 370 pounds. The principal Tin _lode_ in this mine is, in one part, of the enormous width of 30 feet, and is so rich withal, that the adventurers lately gained a clear profit of upwards of £10,000, in the space of three months. The workings extend for more than a mile and a quarter under ground, and about thirteen hundred persons are engaged in conducting its operations.

On the Coast, about three miles west of Helston, is Portleven harbour; notwithstanding the enormous sum of money which has been expended in completing this work, we believe that it is never likely to answer the object for which it was projected; the fact is simply this, that at those times when the severity of the weather renders such a refuge desirable to the navigators of the Mount's Bay, the sea sets in with such tremendous force upon this part of the coast that it is absolutely unsafe for any vessels to approach it, and still more so to attempt a passage into the basin, through its narrow entrance.

HELSTON is a large and populous town, containing nearly 3000 inhabitants, situated on the side of a hill which slopes gradually to the little river _Cober_. The houses are chiefly disposed in four streets in the form of a cross, and, at the point of intersection, stand the market house and town hall. The church, which was erected A.D. 1762, at the sole expense of the then Earl of Godolphin, stands on an eminence to the north, and forms a very pleasing object from the valley below, while to the tempest tossed mariner it serves as a useful landmark.

Helston has returned members to Parliament ever since Edward I., being one of the five ancient boroughs of Cornwall. There was formerly a castle, on the site of the present bowling green, but of which no vestige remains. The town is now lighted by means of gas.

In this town we shall be gratified to find the traces of an ancient custom, which the Antiquary has been anxious to trace to so high a source as the Roman _Floralia_, a festival observed by that people, in honour of the Goddess Flora, on the fourth of the Calends of May. It is called the _Furry_, and it is said that its present name alone would discover its origin, were it not satisfactorily pointed out by the time of its celebration. We confess ourselves to have been amongst the happy number[125] who regarded the annual festival of Helston as a faint trace of the Roman _Floralia_ which the abrasion of fourteen centuries had not wholly obliterated. But the evil genius of Reality has at length appeared to dispel the illusion, and to extort from us the unwilling belief that it can be no other than the anniversary of a victory, obtained by the natives over an invading enemy.

The morning of the _Eighth of May_ is ushered in with the sound of drums and kettles, when the streets are soon thronged with spectators, and assistants in the _Mysteries_. So strict is the observance of this day as a general holiday, that should any person be found at work, he is instantly seized, set astride on a pole, and hurried on men's shoulders to the river, where, if he does not commute his punishment by a fine, he is sentenced to leap over a wide place, which he of course fails in attempting, and falls into the water, to the great amusement of the spectators. At about the hour of nine the revellers appear before the Grammar school, and make their demand of a prescriptive holiday, after which they collect contributions from house to house. They then _fadé_ into the country (_fadé_ being an old English word for _go_), and about noon return with flowers and oak branches in their hats and caps; from this time they dance, hand in hand, through the streets, preceded by a violin,[126] playing an ancient traditional tune, the music of which we shall here introduce.

There is also a traditional song which is sung in chorus, involving the history of Robin-Hood, whose connection with the present festival it is not easy to understand.

Upon this occasion it is a right, assumed from time immemorial, for the persons engaged in the dance to enter and run through any house they please, without molestation.

The higher classes of the inhabitants having, with much good humour, assisted in the rites of the day, and performed their _exforensic_ orgies, resort to the ball room, where they are usually met by the neighbouring families, and by those strangers who may happen to be in this part of Cornwall. The merry dance is commenced at an early hour, and generally protracted to the dawn of the ensuing day.

Long may this harmless and innocent festival continue to animate the blythe and young, on each annual return of its celebration;--Its classic spell may be dissolved, but the Temple of Hilarity, consecrated by the smiles of Cornish youth and beauty, needs not a Roman goddess for its sanction.

Why ask where the Flora derives its gay birth!
Why each smiling brow wears its garland to-day?
Enough that our sires kept it sacred to mirth,
And their children have hearts all as fervent as they.

And yet might we trace where his ashes are laid
Who first made the _Fadé_ to sound in our bowers,
To-day round his cromlech the dance should we braid,
And the fairest of Hellas[127] enwreath it with flowers.

And hallow'd for aye be their place of repose,
Who their race have enrich'd with a dowry so rare,
A spell--that yet brightens each year as it flows
With one gleam of Eden--a day free from care.

Then join we the Dance! to their mem'ries of yore,
Let the mirth which they lov'd be the homage we pay.
And the strain that inspir'd them long ages before,
Wake the joys, which they felt, in our bosoms to-day.

About two miles from Helston is _Penrose_, the seat of John Rogers, Esq. situated in the midst of a finely wooded scene, and on the border of a large sheet of water called the _Loe Pool_; this forms one of the most considerable lakes in the county, and is produced by a very singular operation of nature,--the continual rolling of the waves of the British Channel towards the shore forces in a vast quantity of sand and pebbles, which, by constant accumulation, at length forms a very high bank extending across the valley, from hill to hill, and by closing up the mouth of the channel occasions the river to spread its waters over an area of nearly seven miles in circumference. This bar of gravel cannot be passed over by the waves of the highest tides, even during the excitement of a storm, unless it be attended with a very rare combination of circumstances. The water of the lake gradually finds its way through the gravel of the bar by slow filtration; but in wet seasons, as it cannot pass off with a rapidity equal to its influx, the lake will often rise ten feet higher than its ordinary level. This produces the singular effect of stopping two mills, one on the _Loe_, the other on a lateral stream, their wheels being at this time partly under water. When this occurs the millers present the Lord of the Manor with two leathern purses, each containing three halfpence, and solicit his permission to open a passage through the bar. This being of course granted, the Mayor of Helston engages workmen to carry the work into effect. In a few days, however, the bar is again filled up as before.

The _Loe Pool_ abounds with a peculiar trout, and other fresh-water fish. On its banks the Botanist may gather _Corrigiola Littoralis_.

In proceeding to the Lizard Point, which is about fourteen miles distant from Helston, we shall examine the line of coast south of the Loe bar. The interior of this peninsular region has an aspect of dreary and barren uniformity, and when viewed from the high granite ridge near Constantine, it appears like a table land elevated some hundred feet above the level of the sea, presenting hardly any indication of rupture or contortion throughout the whole extent of its outline. The view of the same region from the western shore of the Mount's Bay is still more striking and characteristic; the upper surface seems so exactly horizontal, that one might almost be led to conjecture, that every projecting ledge had been planed down until the promontory resembled a great artificial terrace.[128]

Near _Gunwalloe Cove_ the geologist should notice the singularly contorted appearance of the slaty rock, which continues as far as a small cove north of _Mullion_, called _Bolerium_, where it runs under a _Greenstone_ composed of _Hornblende_ and _Compact Felspar_. The _Greenstone_ prevails through the whole of this district, and appears to pass by a slow gradation into _Serpentine_, under which it lies, as may be distinctly seen near the south side of _Mullion Cove_.[129] A small quantity of _Diallage_ is occasionally present in this rock, but the predominant ingredient is common _Hornblende_; and where this latter substance greatly predominates over the _Felspar_, it in some places assumes an earthy appearance and decomposes into a kind of _Clay_, which is used in the neighbourhood with excellent effect as a top dressing for grass lands.

_Serpentine_ is the next formation which we discover in our progress, and is that which confers such singular interest upon this part of the county, since it occurs in no other part of England. This beautiful rock derives its name from the variegated colours and spots, supposed to resemble the speckles of a serpent's skin; it is principally of a dark green or brown, suffused with shades of red. It occupies not less than one-third of the area of the peninsula; the whole extent of _Goonhilly downs_ rests on it. Its boundary is easily traced, says _Mr. Sedgwick_, by the brown scanty vegetation with which its surface is imperfectly covered; and the Professor might have added, by the growth of that beautiful heath, the _Erica Vagans_, for so congenial and essential would a Magnesian soil appear to its production, that notwithstanding its immense profusion on the downs, not a single specimen is to be found beyond the line which defines the boundary of the _Serpentine_ formation, nor is it to be seen in any other part of England. _Genista Anglica_ is also to be found on these downs.

About three miles south of Mullion, close to the shore, is the celebrated _Steatite_, or _Soap Rock_, which appears to run in veins[130] in the Serpentine, although Dr. Thomson is inclined to consider it as Serpentine itself in a state of decomposition. When it is first quarried it is soft, but by exposure to air it gradually hardens, although it never loses that peculiar _soapy_ feel which characterises it. Dillwyn & Co. of Swansea have, at present, the works in their possession, by paying to the proprietor, Lord Falmouth, a certain annual sum. Its value in the manufacture of China depends upon its infusibility, and the property it possesses of retaining its colour in the heat of the furnace; the first quality is to be explained by the total absence of lime in its composition, the latter by the very small proportion of metallic matter contained in it. There is, moreover, another purpose which it serves, depending upon the peculiar property of _Magnesian earth_ in preventing that degree of contraction[131] which always occurs in the fire when _Alumina_ and _Silica_ are alone made use of. Near this spot veins of _Native Copper_ may be frequently seen at low water during spring tides, and a mass of this metal was once raised which weighed 104 pounds. Copper is the only metallic substance that has been found in any quantity in the Serpentine formation; and this has never occurred except _native_, as in the above instance, or in the state of _Green Carbonate_, so that the mining adventurer need not anticipate much advantage from it.

About a mile farther south is KYNANCE COVE, justly celebrated as one of the most interesting and extraordinary spots on the coast; the descent into it is extremely steep, and overhung with frowning crags; the cove itself is formed by a numerous assemblage of Serpentine rocks of a dark colour, and which exhibit a beautiful polish from the constant attrition of the waves at high water; in one part, these groups are so singularly disposed as to open a fine natural arch into a grotto, which penetrates deeply into the cliff; the largest of these pyramidal masses is termed the ASPARAGUS ISLAND, from its being the habitat of _Asparagus Officinalis_. One of the rocks in this cove exhibits a very curious phenomenon whimsically called the DEVIL'S BELLOWS; there is a very deep chasm, through which the sea rushes like a water spout, preceded by a sub-marine rumbling, as loud as thunder; a flowing tide, accompanied with a swell of the waves, seems to be essential for the production of this effect. De Luc offers the following explanation of the phenomenon: "In the rock there is a succession of caverns, into which the agitated sea rushes by some sub-marine passage, and being dashed and broken against their sides, a large quantity of air[132] is thus disengaged from them, which becoming highly compressed, and not being able to escape beneath, in consequence of the perpetual entrance of the waves, is forced to pass with great violence and noise from cavern to cavern, until it forces itself, together with a column of water, through the opening above." Amongst these beautiful rocks may be seen _Diallage_ of a brown colour; _Jade_; _compact Felspar_, or _Saussurite_; and _Asbestus_. _Dykes of Felspar Porphyry_ are also to be observed in this spot. It is hardly necessary to inform the geological tourist that, in order to view this interesting scene to his satisfaction, he must contrive to arrive at a period near that of low water.

On the summit of the hill above this cove the Botanist will observe _Geranium Sanguineum_ spreading itself in broad tufts. _Campanula Rotundifolia_ also occurs here.

Continuing our route towards Cape Lizard, we shall perceive that the _Serpentine_ terminates about half a mile before we reach it, and is succeeded by _Micaceous Slate_, under which, at the Lizard head lie alternate beds of _Compact Felspar_, containing specks of _Hornblende_ and _green Talc_. There are two light-houses at this point which front the south, and stand nearly abreast of each other, but unhappily they are too often found to be insufficient securities against the darkness of the midnight storm, and the treachery of the sunken rocks with which this stern coast is beset. Foreign pilots, unacquainted with its perils, seldom keep the necessary distance from the shore, and from the steepness of the rocks no kind of assistance can be afforded to the mariner from the land.

On a low hedge under the light-houses is to be found _Herniaria Glabra_. It was here in the pursuit of this very plant that a well known Botanist, during the late war, was seized as a spy by the suspicious natives, and carried to Helston for examination. The increased intercourse, however, with scientific travellers, will render the recurrence of such an event impossible.

The name of the promontory was most probably derived from the striking _contour_ which it exhibits when viewed from sea, resembling the elongated and compressed form of the Lizard; at the same time it must be observed, that the colour of its rocks resemble also that of the animal to which we allude, while the British words _Lis-ard_ signify a lofty projection; these are extraordinary coincidences, and are well calculated to fan the flame of etymological controversy.

If after visiting this promontory, the traveller feels inclined to trace the different rock formations, and to complete his geological survey of the Lizard _Chersonesus_, we recommend him to return by a circuitous route along its eastern coast. _Greenstone_ reappears about half a mile east of the Lizard Point, and continues for some distance, with the occasional interruption of Serpentine, which dips towards the sea. This latter rock will be found best adapted for oeconomical purposes at the _Balk Hill_, _Landewednock_, but it is certainly far inferior to that worked for chimney pieces, columns, &c. from the quarries in the Isle of Anglesea. Near _Cadgwith_ the rocks on the coast form a very interesting and extraordinary amphitheatre, which is termed by the inhabitants the FRYING PAN, although the appellation of CAULDRON, which it strongly resembles, would be much more appropriate. Its sides are nearly two hundred feet in height, and, at high water, the sea enters it and boils up through an arch near its bottom. In this spot the position of the _Serpentine_ upon _Greenstone_ is very apparent. Beyond _Cadgwith_ the _Serpentine_ assumes a dark green colour, and contains small masses of the emerald green _Diallage_, or _Schiller-spar_; whence it continues to constitute the coast round the _Black Head_ to _Coverack Cove_. About a mile from the coast at _Gwenter_, the rock denominated by Abbe Haüy "_Diallage Rock_" (_Gabbro_) presents itself to our notice; it is composed of _Saussurite_, or _Compact Felspar_, and _Diallage Metalloïde_. In a quarry near this spot it may be seen to join _Serpentine_. In the _Diallage Rock_, at a small village near the coast called _Gwendra_, as well as in the rock of _Saint Keverne_, Mr. Majendie discovered some small metallic specks, which he found on chemical examination to consist of Iron, with a portion of _Titanium_. Some of the same substance was immediately transmitted to Mr. William Gregor, who stated that the results of his experiments proved it to be an assemblage of several ingredients, _viz_. _Silica_, _Alumina_, and the _Oxides of Iron_ and _Titanium_, with a little _Potass_. Some of which ingredients were no doubt derived from the _gangue_ with which the metallic substance is intimately mixed. This is a discovery no less curious than important, and would seem to point out the origin of the _Menachanite_, in which _Titanium_ was first discovered by Mr. Gregor.

The great mass of _Serpentine_ ends at _Coverack Cove_, a spot which well deserves the attention of the Geologist, as offering a series of rocks of a very mixed character; these consist of green and reddish-brown _Serpentine_, with the _Jade_ of Saussure, (the _feldspath tenace_ of Haüy) and _Diallage_[133] of the green and metalloïde varieties; some of the _Felspar_ found here is of a violet colour, and is striated like that of Labrador. In beds which lie below high-water mark in this Cove the mineralogist may obtain masses of _Diallage Metalloïde_, six or eight inches in length.[134] A beautiful rock succeeds and continues for three miles along the coast to the _Manacles_; and in the interior of the country it predominates through the greater part of the parish of _Saint Keverne_. It has _compact Felspar_ for its base, in which are imbedded crystals both of _Diallage_ and _Hornblende_. In the proportion, as well as the magnitude of these constituents, says Mr. Professor Sedgwick, there is such an unusual variety, that we were almost led to conjecture, that during the deposition of the mass many conflicting principles had been in action, not one of which was long able to keep the mastery over the others; there are for instance many large blocks which in one part resemble a fine _Greenstone_, and in another, a coarse porphyritic _Diallage Rock_; within the distance of a few feet these varieties may be observed to alternate repeatedly, sometimes in the form of stripes, but more frequently in amorphous concretions separated from each other by lines which are perfectly defined. _Schistose Greenstone_ occurs again at _Porthowstock_, and a small bed of _Serpentine_, on the south-west side of _Porthallo_ in the cliff, which rests on a reddish _Talc_ which lies, as before, on _Clay-slate_. No other variety is observable from hence to the Helford River, except in the appearance of a _Pudding Stone_, or _Conglomerate_, near the _Dennis Creek_, composed of rounded fragments of Slate in which veins of _Quartz_ are distinctly visible. The traveller will not fail to visit the stream of _Tregonwell Mill_,[135] near the village of _Menacchan_, celebrated as the habitat of the _Titaniferous Iron_ (_Menacchanite_, or _Gregorite_) discovered by the late celebrated Mr. William Gregor.[136] He will also receive much gratification by extending his route to _Mawnan_ Cliffs, where he will observe a most extraordinary intermixture of fine and coarse grained (_Grawacke?_) slate, which are traversed by many contemporaneous veins, some composed of _Quartz_, and others of _Ferriferous_ _Carbonate of Lime_; some small cavities are coated with fine spicular _Arragonite_, and a much rarer substance, which on a chemical examination by Mr. Gregor proved to be a _Sub-carburet of Iron_, has been found in thin plates among the laminæ of the Slate. The Reverend John Rogers has also obtained from this spot small octohedral crystals of the _Yellow Sulphuret of Copper_.

From a general review of the phenomena developed in the present excursion, Mr. Professor Sedgwick is led to conclude, that the _great Plateau of the Lizard is not composed of stratified rocks_, for although some obscure indications of an order of super-position appear near _Coverack_ and _Porthalla_, yet he considers them as being too uncertain to be opposed to the clear evidence offered to the south-eastern parts of the coast, where the alternating masses of _Greenstone_ and _Serpentine_ so often appear, like great wedges driven side by side into the escarpment, without any arrangement whatsoever. Mr. Majendie, however, who, be it known, actually _bivouacked_ in this district for a week, was satisfied that the _Greenstone_ and _Serpentine_ did exhibit characters of Stratification.--But we desist--feeling what no doubt our readers have likewise experienced the dry and uninviting nature of Geological details.--Having therefore completed the task we assigned ourselves, and conducted the traveller to the more prominent and interesting objects of WESTERN CORNWALL, we take our leave. The Agriculturist, the Antiquary, the Botanist, the Geologist, and Mineralogist, must, each in his turn, have received ample gratification and instruction from his visit to this interesting and important district of the British Empire, while the Capitalist must have seen from the agriculture, the mineral treasures, the fisheries, and the commerce of the country, how many, and what great opportunities are presented for the advantageous exercise of capital; the Valetudinarian too has, as we sincerely hope, derived his share of benefit from the excursions, and felt the salutary influence of those mild and genial breezes which clothe our fields with perpetual verdure, and impart to our cottagers the enviable blessing of HEALTH and LONG LIFE.

FOOTNOTES:

[123] Before his departure upon this excursion, we recommend him to examine the very instructive suite of specimens which were collected, and deposited in the Cabinet at Penzance by _Mr. Ashhurst Majendie_, a gentleman whose geological labours in this country are well known, and whose zeal and ability so greatly promoted the early advancement of our Geological Society. This valuable series has been greatly augmented by a Collection since presented to the Society by _The Reverend John Rogers_. The Geological tourist ought at the same time to make himself acquainted with the observations of _Mr. Majendie_ "_On the Lizard District_," in the first volume of the Transactions of the Royal Geological Society of Cornwall; and those of _Mr. Professor Sedgwick_, on the same subject, in the Transactions of the Cambridge Philosophical Society.

[124] In the _Greeb-rock_, an insulated mass of greenstone in the sea beneath, there is a vein of _Asbestus-Actynolite_, mixed with _Axinite_, from four to twelve inches wide. This is a curious spot, well worthy the attention of the geologist.

[125] As will appear on the perusal of the first edition of this little work.

[126] A violin is in some parts of Cornwall called a _Crowd_, whence doubtless the name of _Crowdero_, the fiddler in Hudibras.

[127] The ancient name of Helston. The modern apellation is derived from a huge block of Granite which may be seen in the yard of the Angel Inn--_Hellas-stone_, or _Helston_.

[128] On the physical structure of the Lizard district, by the Rev. A. Sedgwick.

[129] The same relative position of these rocks may also be observed at _Cadgwith_, an interesting part of the coast north-east of the Lizard Point, and which we shall have occasion to notice hereafter.

[130] Sir H. Davy, in a paper on the Geology of Cornwall, published in the first volume of our Transactions, observes that "the nature and origin of the veins of _Steatite_ in Serpentine are curious subjects of inquiry. Were they originally crystallized, and the result of chemical deposition? Or have they been, as for the most part they are now found, mere mechanical deposites, I am inclined to the last opinion. The _Felspar_ in Serpentine is very liable to decompose, probably from the action of Carbonic acid and water on its Alkaline, Calcareous, and Magnesian elements; and its parts washed down by water, and deposited in the chasms of the rocks, would necessarily gain that kind of loose aggregation belonging to Steatite."

[131] It might on this account be worth while for the Glass-maker to try the effects of a small mixture of _Steatite_ with the materials of which he makes his large crucibles, in order to prevent that great degree of shrinking to which they are now so liable.

[132] The quantity of air thus separated from water is so great that in the Alps and in the Pyrennees, very powerful bellows are made for forges by the fall of a column of water, through a wooden pipe, into a closed cask, in which it dashes on a stone in the bottom, when the air thus disengaged from it is carried by another pipe placed in the cover of the cask into the foundery.

[133] This substance presents with great distinctness those characters which distinguish it from _Hornblende_, viz. inferior hardness, difficult fusibility into a green enamel, and peculiar cleavage which discovers a considerable lustre in one direction which is entirely absent in the other; whereas _Hornblende_ has natural joints of the same lustre in two directions.

[134] Mr. Majendie presented some of these specimens to Abbe Haüy, and compared them with those in the cabinet of that illustrious mineralogist, which were brought from the hill of _Mussinet_ near Turin. M. Haüy observed upon this occasion, that the Coverack Specimens did not consist of pure _Diallage_, but that fibres of common _Hornblende_ interrupted its texture. That of _Mussinet_ is foliated, and has no such intermixture.

[135] For a long period this was considered as the only Cornish habitat of this mineral; but Dr. Paris subsequently identified its presence in a sand brought from a stream near the house of Colonel Sandys at Lanarth. See "Transactions of the Royal Geological Society of Cornwall." Vol. I. p, 226.

[136] See a History of this curious discovery in "A Memoir on the Life and Scientific Labours of the Rev. William Gregor, by J. A. Paris, M. D."--London, 1818.

APPENDIX.