universally used in the country wherever pitch is required'; and the reports of the naval officers who' have tried it are favourable to its more general adoption: it is requisite merely to prepare it with a proportion of oil, tallow, or common tar, to give it a sufficient degree of fluidity. In this point of view, this lake is of vast national importance, and more especially to a great maritime power. It is indeed singular that the attention of government should not have been more forcibly directed to a subject of such magnitude: the attempts that have hitherto been made to render it extensively useful have, for the most part, been only feeble and injudicious, and have consequently proved abortive. This vast collection of bitumen' might in all probability afford an inexhaustible supply of an essential article of naval stores, and being situated on the margin of the sea could be wrought and shipped with little inconvenience or expense.* It would be great injustice to Sir Alexander Cochrane not to state explicitly, that he has at various times during his long and active command on the Leeward Island station, taken considerable pains to insure a proper and fair trial of this mineral production for the highly important uses of which it is generally believed to be capable. But whether it has arisen from certain perverse occurrences or from

the prejudice of the mechanicalsuperintendents of the colonial dockyards, or really, as some have pretended, from an absolute unfitness of the substance in question; the views of the gallant admiral have, I believe, been invariably thwarted, or his exertions rendered altogether fruitless. I was at Antigua in 1809, when a transport arrived laden with this pitch for the use of the dock-yard at English Harbour: it had evidently been hastily collected with little care or zeal, from the beach, and was, of course, much contaminated with sand and other foreign substances. The best way would probably be, to have it properly prepared on the spot, and brought to the state in which it may be serviceable, previously to its exportation. I have frequently seen it used to pay the bottoms of small vessels, for which it is particularly well adapted, as it preserves them from the numerous tribe of worms so abundant in tropical countries.+ There seems indeed no reason why it should not when duly prepared and attenuated be applicable to all the purposes of the petroleum of Zante, a wellknown article of Commerce in the Adriatic, or that of the district in Burmah, where 400,000 hogsheads are said to be collected annually.t

It is observed by Capt. Mallet, in his Short Topographical Sketch, of the island, that "near Cape la Brea (la Brave) a little to the

VOL. LIII.

south-west, is a gulf or vortex, which in stormy, weather gushes out, raising the water five or six feet, and covers the surface for a considerable space with petroleum or tar:" and he adds, that " on the east coast in the Bay of Mayaro, there is another gulf or vortex similar to the former, which in the months of March and June produces a detonation like thunder, having some flame with a thick black smoke, which vanishes away immediately; in about twenty-four hours afterwards is found along the shore of the bay a quantity of bitumen or pitch, about three or four inches thick, which is employed with success." Captain Mallet likewise quotes Gumilla, as stating in his Description of the Orinoco, that about seventy years ago "a spot of land on the western coast of this Island, nearly half way between the capital, an Indian village sank suddenly, and was immediately replaced by a small, lake of pitch, to the great terror of the inhabitants."

I have had no opportunity of ascertaining personally whether these statements are accurate, though sufficiently probable from what is known to occur in other parts of the world; but I have been informed by several persons that the sea in the neighbourhood of La Braye is occasionally covered with a fluid bitumen, and in the south-eastern part of the island there is certainly a similar collection of this bitumen, though of less extent, and many small detached spots of it are to be met with in the woods; it is even said that an evident line of communication may thus be traced between

the two great receptacles. There is every probability, that in all these cases the pitch was originally fluid, and has since become inspissated by exposure to the air, as happens in the Dead Sea and other parts of the East.

It is for geologists to explain the origin of this singular phænomenon, and each sect will doubtless give a solution of the difficulty according to its peculiar tenets. To frame any very satisfactory hypothesis on the subject, would require a more exact investigation of the neighbouring country, and particularly to the southward and eastward, which I had not an opportunity of visiting. And it must be remembered, that geological inquiries are not con-. ducted here with that facility which they are in some other parts of the world: the soil is almost universally covered with the thickest and most luxuriant vegetation, and the stranger is soon exhausted and overcome by the scorching rays of a vertical sun. Immediately to the southward, the face of the country, as seen from la Braye, is a good deal broken and rugged, which Mr. Anderson attributes to some convulsion of nature from subterranean fires, in which idea he is confirmed by having found in the neighbouring woods several hot springs. He is indeed of opinion that this tract has experienced the effects of the volcanic power, which, as he supposes, elevated the great mountains on the main and the northern side of the island. The production of all bituminous substances has certainly with plausibility been attributed to the action

pledging myself to any particular system of geology, I confess an explanation similar to this appears to me sufficiently probable, and consonant with the known phanomena of nature. A vast river, like the Orinoco, must for ages have rolled down great quantities of woody and vegetable bodies, which from certain causes, -as the influence of currents and eddies, may have arrested and accumulated in particular places; they may there have undergone those transformations and chemical changes which various vegetable substances similarly situated have been proved to suffer in other parts of the world. An accidental fire, such as is known frequently to occur in the bowels of the earth, may then have operated in separating and driving off the newly-formed bitumen more or less combined with siliceous andargillaceous earth's, which forc. ing its way through the surface, and afterwards becoming inspis sated by exposure to the air, may have occasioned such scenes as I havé ventured to describe. The only other country accurately resembling this part of Trinidad, of which I recollect to have read, is that which borders on the gulf of Taman in Crim Tartary: from the representation of travellers," springs of naphtha and petroleum equally abound, and they describe volcanic mounds precisely similar to those of Point Icaque. Pallas's explanation of their origin seems to me very satisfactory; and I think it not improbable that the river Don and sea of Azof may

have acted the same part in producing these appearances in the one case, as the Orinoco and Gulf of Paria appear to have done in the other. It may be supposed that the destruction of a forest, or perhaps even a great savanna on the spot, would be a more obvious mode of accounting for this singular phænomenon; but, as I shall immediately state, all this part of the island is of recent alluvial formation, and the land all along this coast is daily receiving a considerable accession from the surrounding water. The pitch lake with the circumjacent tract being now on the margin of the sea, must in like manner have had an origin of no very distant date; besides, according to the above representation of Capt. Mallet, and which has been frequently corroborated, a fluid bitumen oozes up and rises to the surface of the water on both sides of the island, not where the sea has encroached on and overwhelmed the ready-formed land, but where it is obviously in a very rapid manner depositing and forming a new soil.

From a consideration of the great hardness, the specific gravity, and the general external characters of the specimens submitted a few years ago to the examina-* tion of Mr. Hatchett, that gentleman was led to suppose that a considerable part of the aggregate mass at Trinidad was not pure mineral pitch or asphaltum, but rather a porous stone of the argillaceous genus, much impregnated with bitumen. Two specimens of the more compact and earthy sort,

*

analysed by Mr. Hatchett, yielded about 32 and 36 per cent, of pure bitumen: the residuum in the crucible consisted of a spongy, friable and ochraceous stone; and 100 parts of it afforded, as far as could be determined by a single trial, of silica 60, alumina 10, oxide of iron 10, carbonaceous matter by estimation 11; not the smallest traces of lime could be discovered; so that the substance has no similarity to the bituminous limestones which have been noticed in different parts of the world. I have already remarked, that this mineral production differs considerably in different places. The specimens examined by Mr. Hatchett by no means correspond in character with the great mass of the lake, which, in most cases, would doubtless be found to be infinitely more free from combination with earthy substances; though from the mode of origin which I have assigned to it, this intermixture may be regarded as more or less unavoidable. The analysis of the stone after the separation of the bitumen, as Mr. Hatchett very correctly observes, accords with the prevalent soil of the country; and I may add, with the soil daily deposited by the gulf, and with the composition of the porcelain jasper in immediate contact with the bituminous mass. All the country which I have visited in Trinidad is either decidedly primitive or alluvial. The great northern range of mountains which runs from east to west, and is connected with the Highlands of Paria on the continent by the Islands at the Bocas, consists of

gneiss, of mica slate containing great masses of quartz, and in many places approaching so much to the nature of talc as to render the soil quite unctuous by its decomposition, and of compact blueish gray limestone, with frequent veins of white crystallized carbonate oflime. From the foot of these mountains, for many leagues to the southward, there is little else than a thick fertile argillaceous soil, without a stone or a single pebble. This tract of land, which is low and perfectly level, is evidently formed by the detritus of the mountains, and by the copious tribute of the waters of the Orinoco, which being deposited by the influence of currents, gradually accumulates; and, in a climate where vegetation is astonishingly rapid, is speedily covered with the mangrove and other woods. It is accordingly observed, that the leeward side of the island constantly encroaches on the gulf, and ma, rine shells are frequently found on the land at a considerable distance from the sea. This is the charac ter of Naparima and the greater part of the country I saw along the coast to la Braye. It is not only in forming and extending the coast of Trinidad, that the Orinoco exerts its powerful agency; cooperating with its mighty sister flood, the Amazons, it has manifestly formed all that line of coast and vast extent of country included between the extreme branches of each river, To use the language of a writer in the Philosophical Transactions of Edinburgh: "If you cast your eye upon the map, you will ob