The tertiary rocks which form such remarkable features in the geology of other countries are almost unknown in Ceylon; and the "clay-slate, Silurian, old red sandstone, carboniferous, new red sandstone, oolitic, and cretaceous systems" have not as yet been recognised in any part of the island.[1] Crystalline limestone in some places overlies the gneiss, and is worked for oeconomical purposes in the mountain districts where it occurs.[2]
[Footnote 1: Dr. Gardner.]
[Footnote 2: In the maritime provinces lime for building is obtained by burning the coral and madrepore, which for this purpose is industriously collected by the fishermen during the intervals when the wind is off sh.o.r.e.]
Along the western coast, from Point-de-Galle to Chilaw, breccia is found near the sh.o.r.es, from the agglutination of corallines and sh.e.l.ls mixed with sand, and the disintegrated particles of gneiss. These beds present an appearance very closely resembling a similar rock, in which human remains have been found imbedded, at the north-east of Guadaloupe, now in the British Museum.[1] Incorporated with them there are minute fragments of sapphires, rubies, and tourmaline, showing that the sand of which the breccia is composed has been washed down by the rivers from the mountain zone.
[Footnote 1: Dr. Gardner.]
NORTHERN PROVINCES.--_Coral Formation_.--But the princ.i.p.al scene of the most recent formations is the extreme north of the island, with the adjoining peninsula of Jaffna. Here the coral rocks abound far above high-water mark, and extend across the island where the land has been gradually upraised, from the eastern to the western sh.o.r.e. The fortifications of Jaffna were built by the Dutch, from blocks of breccia quarried far from the sea, and still exhibit, in their worn surface, the outline of the sh.e.l.ls and corallines of which they mainly consist. The roads, in the absence of more solid substances, are metalled with the same material; as the only other rock which occurs is a loose description of conglomerate, similar to that at Adam"s Bridge and Manaar.
The phenomenon of the gradual upheaval of these strata is sufficiently attested by the position in which they appear, and their alt.i.tude above high-water mark; but, in close contiguity with them, an equally striking evidence presents itself in the fact that, at various points of the western coast, between the island of Manaar and Karativoe, the natives, in addition to fishing for chank sh.e.l.ls[1] in the sea, dig them up in large quant.i.ties from beneath the soil on the adjacent sh.o.r.es, in which they are deeply imbedded[2], the land having since been upraised.
[Footnote 1: _Turbinella rapa_, formerly known as _Voluta gravis_ used by the people of India to be sawn into bangles and anklets.]
[Footnote 2: In 1845 an antique iron anchor was found under the soil at the northwestern point of Jaffna, of such size and weight as to show that it must have belonged to a ship of much greater tonnage than any which the depth of water would permit to navigate the channel at the present day.]
The sand, which covers a vast extent of the peninsula of Jaffna, and in which the coco-nut and Palmyra-palm grow freely, has been carried by the currents from the coast of India, and either flung upon the northern beach in the winter months, or driven into the lake during the south-west monsoon, and thence washed on sh.o.r.e by the ripple, and distributed by the wind.
The arable soil of Jaffna is generally of a deep red colour, from the admixture of iron, and, being largely composed of lime from the comminuted coral, it is susceptible of the highest cultivation, and produces crops of great luxuriance. This tillage is carried on exclusively by irrigation from innumerable wells, into which the water rises fresh through the madrepore and sand; there being no streams in the district, unless those percolations can be so called which make their way underground, and rise through the sands on the margin of the sea at low water.
_Wells in the Coral Rock_.--These phenomena occur at Jaffna, in consequence of the rocks being magnesian limestone and coral, overlying a bed of sand, and in some places, where the soil is light, the surface of the ground is a hollow arch, so that it resounds as if a horse"s weight were sufficient to crush it inwards. This is strikingly perceptible in the vicinity of the remarkable well at Potoor[1], on the west side of the road leading from Jaffna to Point Pedro, where the surface of the surrounding country is only about fifteen feet above the sea-level. The well, however, is upwards of 140 feet in depth; the water fresh at the surface, brackish lower down, and intensely salt below.
According to the universal belief of the inhabitants, it is an underground pool, which communicates with the sea by a subterranean channel bubbling out on the sh.o.r.e near Kangesentorre, about seven miles to the north-west.
[Footnote 1: For the particulars of this singular well, see Vol. II. Pt.
IX. ch. vi. p. 536.]
A similar subterranean stream is said to conduct to the sea from another singular well near Tillipalli, in sinking which the workmen, at the depth of fourteen feet, came to the ubiquitous coral, the crust of which gave way, and showed a cavern below containing the water they were in search of, with a depth of more than thirty-three feet. It is remarkable that the well at Tillipalli preserves its depth at all seasons alike, uninfluenced by rains or drought; and a steam-engine erected at Potoor, with the intention of irrigating the surrounding lands, failed to lower it in any perceptible degree.
Other wells, especially some near the coast, maintain their level with such uniformity as to be inexhaustible at any season, even after a succession of years of drought--a fact from which it may fairly be inferred that their supply is chiefly derived by percolation from the sea.[1]
[Footnote 1: DARWIN, in his admirable account of the coral formations of the Pacific and Indian oceans, has propounded a theory as to the abundance of fresh water in the atolls and islands on coral reefs, furnished by wells which ebb and flow with the tides. a.s.suming it to be impossible to separate salt from sea water by filtration, he suggests that the porous coral rock being permeated by salt water, the rain which falls on the surface must sink to the level of the surrounding sea, "and must acc.u.mulate there, displacing an equal bulk of sea water--and as the portion of the latter in the lower part of the great sponge-like ma.s.s rises and falls with the tides, so will the fresh water near the surface."--_Naturalist"s Journal_, ch. xx. But subsequent experiments have demonstrated that the idea of separating the salt by filtration is not altogether imaginary; as Darwin seems to have then supposed; and Mr.
WITT, in a remarkable paper _On a peculiar power possessed by Porous Media of removing matters from solution in water_, has since succeeded in showing that "water containing considerable quant.i.ties of saline matter in solution may, by merely percolating through great ma.s.ses of porous strata during long periods, be gradually deprived of its salts _to such an extent as probably to render even sea-water fresh_."--_Philos. Mag_., 1856. Divesting the subject therefore of this difficulty, other doubts would appear to suggest themselves as to the applicability of Darwin"s theory to coral formations in general. For instance, it might be supposed that rain falling on a substance already saturated with moisture, would flow off instead of sinking into it; and that being of less specific gravity than salt water, it would fail to "displace an equal bulk" of the latter. There are some extraordinary but well attested statements of a thin layer of fresh water being found on the surface of the sea, after heavy rains in the Bay of Bengal. (_Journ.
Asiat. Soc. Beng_. vol. v. p. 239.) Besides, I fancy that in the majority of atolls and coral islands the quant.i.ty of rain which so small an area is calculated to intercept would be insufficient of itself to account for the extraordinary abundance of fresh water daily drawn from the wells. For instance, the superficial extent of each of the Laccadives is but two or three square miles, the surface soil resting on a crust of coral, beneath which is a stratum of sand; and yet on reaching the latter, fresh water flows in such profusion, that wells and large tanks for soaking coco-nut fibre are formed in any place by merely "breaking through the crust and taking out the sand."--_Madras Journal_, vol. xiv. It is curious that the abundant supply of water in these wells should have attracted the attention of the early navigators, and Cosmas Indicoplenstes, writing in the sixth century, speaks of the numerous small islands off the coast of Taprobane, with abundance of fresh water and coco-nut palms, although these islands rest on a bed of sand.
(_Cosmas Ind_. ed. Thevenot, vol. i. p. 3, 20). It is remarkable that in the little island of Ramisseram, one of the chain which connects Adam"s Bridge with the Indian continent, fresh water is found freely on sinking for it in the sand. But this is not the case in the adjacent island of Manaar, which partic.i.p.ates in the geologic character of the interior of Ceylon. The fresh water in the Laccadive wells always fluctuates with the rise and fall of the tides. In some rare instances, as on the little island of Bitra, which is the smallest inhabited spot in the group, the water, though abundant, is brackish, but this is susceptible of an explanation quite consistent with the experiments of Mr. Witt, which require that the process of percolation shall be continued "during _long_ periods and through _great ma.s.ses of porous strata_;" Darwin equally concedes that to keep the rain fresh when banked in, as he a.s.sumes, by the sea, the ma.s.s of madrepore must be "sufficiently thick to prevent mechanical admixture; and where the land consists of loose blocks of coral with open interstices, the water, if a well be dug, is brackish." Conditions a.n.a.logous to all these particularised, present themselves at Jaffna, and seem to indicate that the extent to which fresh water is found there, is directly connected with percolation from the sea. The quant.i.ty of rain which annually falls is less than in England, being but thirty inches; whilst the average heat is highest in Ceylon, and the evaporation great in proportion. Throughout the peninsula, I am informed by Mr. Byrne, the Government surveyor of the district, that as a general rule "_all the wells are below the sea level_." It would be useless to sink them in the higher ground, where they could only catch surface water. The November rains fill them at once to the brim, but the water quickly subsides as the season becomes dry, and "_sinks to the uniform level, at which it remains fixed for the next nine or ten months_, unless when slightly affected by showers."
"_No well below the sea level becomes dry of itself_," even in seasons of extreme and continued drought. But the contents do not vary with the tides, the rise of which is so trifling that the distance from the ocean, and the slowness of filtration, renders its fluctuations imperceptible.
On the other hand, the well of Potoor, the phenomena of which indicate its direct connection with the sea, by means of a fissure or a channel beneath the arch of magnesian limestone, rises and falls a few inches in the course of every twelve hours. Another well at Navokeiry, a short distance from it, does the same, whilst the well at Tillipalli is entirely unaffected as to its level by any rains, and exhibits no alteration of its depths on either monsoon. ADMIRAL FITZROY, in his _Narrative of the Surveying Voyages of the Adventure and Beagle_, the expedition to which Mr. Darwin was attached, adverts to the phenomenon in connection with the fresh water found in the Coral Islands, and the rise and fall of the wells, and the flow and ebb of the tide. He advances the theory propounded by Darwin of the retention of the river-water, which he says, "does not mix with the salt water which surrounds it except at the edges of the land. The flowing tide pushes on every side, the mixed soil being very porous, and causes the water to rise: when the tide falls, the fresh water sinks also. _A sponge full of fresh water placed gently in a basin of salt water, will not part with its contents for a length of time if left untouched_, and the water in the middle of the sponge will be found untainted by salt for many days: perhaps much longer if tried."--Vol. i. p. 365. In a perfectly motionless medium the experiment of the sponge may no doubt be successful to the extent mentioned by Admiral Fitzroy; and so the rain-water imbibed by a coral rock might for a length of time remain fresh where it came into no contact with the salt. But the disturbance caused by the tides, and the partial intermixture admitted by Admiral Fitzroy, must by reiterated occurrence tend in time to taint the fresh water which is affected by the movement: and this is demonstrable even by the test of the sponge; for I find that on charging one with coloured fluid, and immersing it in a vessel containing water perfectly pure, no intermixture takes place so long as the pure water is undisturbed; but on causing an artificial tide, by gradually withdrawing and as gradually replacing a portion of the surrounding contents of the basin, the tinted water in the sponge becomes displaced and disturbed, and in the course of a few ebbs and flows its escape is made manifest by the quant.i.ty of colour which it imparts to the surrounding fluid.]
An idea of the general aspect of Ceylon will be formed from what has here been described. Nearly four parts of the island are undulating plains, slightly diversified by offsets from the mountain system which entirely covers the remaining fifth. Every district, from the depths of the valleys to the summits of the highest hills, is clothed with perennial foliage; and even the sand-drifts, to the ripple on the sea line, are carpeted with verdure, and sheltered from the sunbeams by the cool shadows of the palm groves.
SOIL.--But the soil, notwithstanding this wonderful display of spontaneous vegetation, is not responsive to systematic cultivation, and is but imperfectly adapted for maturing a constant succession of seeds and cereal productions.[1] Hence arose the disappointment which beset the earliest adventurers who opened plantations of coffee in the hills, on discovering that after the first rapid development of the plants, delicacy and languor ensued, which were only to be corrected by returning to the earth, in the form of manures, those elements with which it had originally been but sparingly supplied, and which were soon exhausted by the first experiments in cultivation.
[Footnote 1: See a paper in the Journal of Agriculture, for March, 1857, Edin.: on _Tropical Cultivation and its Limits_, by Dr. MACVICAR.]
_Patenas_.--The only spots. .h.i.therto found suitable for planting coffee, are those covered by the ancient forests of the mountain zone; and one of the most remarkable phenomena in the oeconomic history of the island, is the fact that the gra.s.s lands on the same hills, closely adjoining the forests and separated from them by no visible line save the growth of the trees, although they seem to be identical in the nature of the soil, have hitherto proved to be utterly insusceptible of reclamation or culture by the coffee planter.[1] These verdant openings, to which the natives have given the name of _patenas_, generally occur about the middle elevation of the hills, the summits and the hollows being covered with the customary growth of timber trees, which also fringe the edges of the mountain streams that trickle down these park-like openings. The forest approaches boldly to the very edge of a "patena," not disappearing gradually or sinking into a growth of underwood, but stopping abruptly and at once, the tallest trees forming a fence around the avoided spot, as if they enclosed an area of solid stone. These sunny expanses vary in width from a few yards to many thousands of acres; in the lower ranges of the hills they are covered with tall lemon-gra.s.s _(Andropogon schoenanthus)_ of which the oppressive perfume and coa.r.s.e texture, when full grown, render it distasteful to cattle, which will only crop the delicate braird that springs after the surface has been annually burnt by the Kandyans. Two stunted trees, alone, are seen to thrive in these extraordinary prairies, _Careya arborea_ and _Emblica officinalis_, and these only below an alt.i.tude of 4000 feet; above this, the lemon-gra.s.s is superseded by harder and more wiry species; but the earth is still the same, a mixture of decomposed quartz largely impregnated with oxide of iron, but wanting the phosphates and other salts which are essential to highly organised vegetation.[2] The extent of the patena land is enormous in Ceylon, amounting to millions of acres; and it is to be hoped that the complaints which have hitherto been made by the experimental cultivators of coffee in the Kandyan provinces may hereafter prove exaggerated, and that much that has been attributed to the poverty of the soil may eventually be traced to deficiency of skill on the part of the early planters.
[Footnote 1: Since the above was written, attempts have been made, chiefly by natives to plant coffee on patena land. The result is a conviction that the cultivation is practicable, by the use of manures from the beginning; whereas forest land is capable, for three or four years at least, of yielding coffee without any artificial enrichment of the soil.]
[Footnote 2: HUMBOLDT is disposed to ascribe the absence of trees in the vast gra.s.sy plains of South America, to "the destructive custom of setting fire to the woods, when the natives want to convert the soil into pasture: when during the lapse of centuries gra.s.ses and plants have covered the surface with a carpet, the seeds of trees can no longer germinate and fix themselves in the earth, although birds and winds carry them continually from the distant forests into the Savannahs."--_Narrative_, vol. i. ch. vi. p. 242.]
The natives in the same lofty localities find no deficient returns in the crops of rice, which they raise in the ravines and hollows, into which the earth from above has been washed by the periodical rains; but the cultivation of rice is so entirely dependent on the presence of water, that no inference can be fairly drawn as to the quality of the soil from the abundance of its harvest.
The fields on which rice is grown in these mountains form one of the most picturesque and beautiful objects in the country of the Kandyans.
Selecting an angular recess where two hills converge, they construct a series of terraces, raised stage above stage, and retiring as they ascend along the slope of the acclivity, up which they are carried as high as the soil extends.[1] Each terrace is furnished with a low ledge in front, behind which the requisite depth of water is retained during the germination of the seed, and what is superfluous is permitted to trickle down to the one below it. In order to carry on this peculiar cultivation the streams are led along the level of the hills, often from a distance of many miles, with a skill and perseverance for which the natives of these mountains have attained a great renown.
[Footnote 1: The conversion of the land into these hanging farms is known in Ceylon as "a.s.suedamizing," a term borrowed from the Kandyan vernacular, in which the word "a.s.suedame" implies the process above described.]
In the lowlands to the south, the soil partakes of the character of the hills from whose detritus it is to a great extent formed. In it rice is the chief article produced, and for its cultivation the disintegrated laterite (_cabook_), when thoroughly irrigated, is sufficiently adapted.
The seed time in the southern section of the island is dependent on the arrival of the rains in November and May, and hence the mountains and the maritime districts at their base enjoy two harvests in each year--the _Maha_, which is sown about July and August, and reaped in December and January, the _Yalla_ which is sown in spring, and reaped from the 15th of July to the 20th September. But owing to the different description of seed sown in particular localites, and the extent to which they are respectively affected by the rains, the times of sowing and harvest vary considerably on different sides of the island.[1]
[Footnote 1: The reaping of other descriptions of grain besides rice occurs at various periods of the year according to the locality.]
In the north, where the influence of the monsoons is felt with less force and regularity, and where, to counteract their uncertainty, the rain is collected in reservoirs, a wider discretion is left to the husbandman in the choice of season for his operations.[1] Two crops of grain, however, are the utmost that is taken from the land, and in many instances only one. The soil near the coast is light and sandy, but in the great central districts of Neuera-kalawa and the Wanny, there is found in the midst of the forests a dark vegetable mould, in which in former times rice was abundantly grown by the aid of those prodigious artificial works for irrigation which still form one of the wonders of the island. Many of the tanks, though partially in ruins, cover an area from ten to fifteen miles in circ.u.mference. They are now generally broken and decayed; the waters which would fertilise a province are allowed to waste themselves in the sands, and hundreds of square miles capable of furnishing food for all the inhabitants of Ceylon are abandoned to solitude and malaria, whilst rice for the support of the non-agricultural population is annually imported from the opposite coast of India.
[Footnote 1: This peculiarity of the north of Ceylon was noticed by the Chinese traveller FA HIAN, who visited the island in the fourth century, and says of the country around Anaraj.a.poora: "L"ens.e.m.e.ncement des champs est suivant la volonte des gens; il n"y a point de temps pour cela."--_Fo[)e] Kou[)e] Ki_; p. 332.]
_Talawas_.--In these districts of the lowlands, especially on the eastern coast of the island, and in the country watered by the Mahawelli-ganga and the other great rivers which flow towards the Bay of Bengal and the magnificent estuary of Trincomalie, there are open glades which diversify the forest scenery somewhat resembling the gra.s.sy patenas in the hills, but differing from them in the character of their soil and vegetation. These park-like meadows, or, as the natives call them, "talawas," vary in extent from one to a thousand acres. They are belted by the surrounding woods, and studded with groups of timber and sometimes with single trees of majestic dimensions. Through these pastures the deer troop in herds within gunshot, bounding into the nearest cover when disturbed.
Lower still and immediately adjoining the sea-coast, the broken forest gives place to brushwood, with here and there an a.s.semblage of dwarf shrubs; but as far as the eye can reach, there is one vast level of impenetrable jungle, broken only by the long sweep of salt marshes which form lakes in the rainy season, but are dry between the monsoons, and crusted with crystals that glitter like snow in the sunshine.
On the western side of the island the rivers have formed broad alluvial plains, in which the Dutch attempted to grow sugar. The experiment has been often resumed since; but even here the soil is so defective, that the cost of artificially enriching it has. .h.i.therto been a serious obstruction to success commercially, although in one or two instances, plantations on a small scale have succeeded to a certain extent.
METALS.--The plutonic rocks of Ceylon are but slightly metalliferous, and hitherto their veins and deposits have been but imperfectly examined. The first successful survey attempted by the Government was undertaken during the administration of Viscount Torrington, who, in 1847, commissioned Dr. Gygax to proceed to the hill district south of Adam"s Peak, and furnish a report on its products. His investigations extended from Ratnapoora, in a south-eastward direction, to the mountains which overhang Bintenne, but the results obtained did not greatly enlarge the knowledge previously possessed. He established the existence of _tin_ in the alluvium along the base of the mountains to the eastward towards Edelgashena; but so circ.u.mstanced, owing to the flow of the Walleway river, that, without lowering its level, the metal could not be extracted with advantage. The position in which it occurs is similar to that in which tin ore presents itself in Saxony; and along with it, the natives, when searching for gems, discover garnets, corundum, white topazes, zircon, and tourmaline.
_Gold_ is found in minute particles at Gettyhedra, and in the beds of the Maha Oya and other rivers flowing towards the west.[1] But the quant.i.ty hitherto discovered has been too trivial to reward the search.
The early inhabitants of the island were not ignorant of its presence; but its occurrence on a memorable occasion, as well as that of silver and copper, is recorded in the Mahawanso as a miraculous manifestation, which signalised the founding of one of the most renowned shrines at the ancient capital.[2]
[Footnote 1: Ruanwelle, a fort about forty miles distant from Colombo, derives its name from the sands of the river which flows below it,--rang-welle, "golden sand." "Rang-galla," in the central province, is referable to the same root--the rock of gold.]
[Footnote 2: _Mahawanso,_ ch. xxiii. p. 166, 167.]
_Nickel_ and _cobalt_ appear in small quant.i.ties in Saffragam, and the latter, together with _rutile_ (an oxide of t.i.tanium) and _wolfram_, might find a market in China for the colouring of porcelain.[1]
_Tellurium_, another rare and valuable metal, hitherto found only in Transylvania and the Ural, has likewise been discovered in these mountains, _Manganese_ is abundant, and _Iron_ occurs in the form of magnetic iron ore, t.i.tanite, chromate, yellow hydrated, per-oxide and iron pyrites. In most of these, however, the metal is scanty, and the ores of little comparative value, except for the extraction of manganese and chrome. "But there is another description of iron ore," says Dr.
Gygax, in his official report to the Ceylon Government, "which is found in vast abundance, brown and compact, generally in the state of carbonate, though still blended with a little chrome, and often molybdena. It occurs in large ma.s.ses and veins, one of which extends for a distance of fifteen miles; from it millions of tons might be smelted, and when found adjacent to fuel and water-carriage, it might be worked to a profit. The quality of the iron ore found in Ceylon is singularly fine; it is easily smelted, and so pure when reduced as to resemble silver. The rough ore produces from _thirty_ to _seventy-five_ per cent., and on an average fully _fifty_. The iron wrought from it requires no puddling, and, converted into steel, it cuts like a diamond.
The metal could be laid down in Colombo at 6 per ton, even supposing the ore to be brought thither for smelting, and prepared with English coal; but _anthracite_ being found upon the spot, it could be used in the proportion of three to one of the British coal; and the cost correspondingly reduced."
[Footnote 1: The _Asiatic Annual Register_ for 1799 contains the following:--
"_Extract from a letter from Colombo, dated 26th Oct. 1798_.
"A discovery has been lately made here of a very rich mine of _quicksilver,_ about six miles from this place. The appearances are very promising, for a handful of the earth on the surface will, by being washed, produce the value of a rupee. A guard is set over it, and accounts sent express to the Madras Government."--P. 53. See also PERCIVAL"S _Ceylon_, p. 539.
JOINVILLE, in a MS, essay on _The Geology of Ceylon_, now in the library of the East India Company, says that near Trincomalie there is "un sable noir, compose de detriments de trappe et de cristaux de fer, _dans lequel on trouve par le lavage beaucoup de mercure_."]
Remains of ancient furnaces are met with in all directions precisely similar to those still in use amongst the natives. The Singhalese obtain the ore they require without the trouble of mining; seeking a spot where the soil has been loosened by the latest rains, they break off a sufficient quant.i.ty, which, in less than three hours, they convert into iron by the simplest possible means. None of their furnaces are capable of smelting more than twenty pounds of ore, and yet this quant.i.ty yields from seven to ten pounds of good metal.
The _anthracite_ alluded to by Dr. Gygax is found in the southern range of hills near Nambepane, in close proximity to rich veins of _plumbago_, which are largely worked in the same district, and the quant.i.ty of the latter annually exported from Ceylon exceeds a thousand tons.
_Molybdena_ is found in profusion dispersed through many rocks in Saffragam, and it occurs in the alluvium in grey scales, so nearly resembling plumbago as to be commonly mistaken for it. _Kaolin_, called by the natives _Kirimattie_, appears at Neuera-ellia at Hewahette, Kaduganawa, and in many of the higher ranges as well as in the low country near Colombo; its colour is so clear as to suit for the manufacture of porcelain[1]; but the difficulty and cost of carriage render it as yet unavailing for commerce, and the only use to which it has. .h.i.therto been applied is to serve for whitewash instead of lime.