passage aux montagnes primitives, qui par celle raison forment des chaines, dans une direction, que la crevasse leur a pr scrite. On peut donc s'attendre à un plus grand developpement des agens volcaniques au fond de cette crévasse, que sur les hauteurs.

Le sel gemme est, d'après les recherches les plus récentes, un produit d'une action volcanique ou plutanique le long d'une ouverture de cette nature. Mais, les sources d' asphalte ou de bitume le sont aussi; comme le prouvent la quantit de sources de bitume depuis le pied du Zagros aux environs de Bassorah jusqu'à Mosul et à Bakou; comme le prouvent encore le source de bitume dans le golfe de Naples, ou à Mellitti près de Siracuse; comme le prouvent les sources de bitume sur l'isle de Zante, et même le bitume de Seyssel dont on fait les trottoirs à Paris.

L'Asphalte de la Mer Morte n'est vrais-semblablement que le bitume consolidé au fond du lac, qui ne peut pas s'écouler, et forme par conséquent une couche sur ce fond, comme à l'isle de Trinidad. Il est assez vrais-semblable, que celle accumulation se soit faite dans les temps reculés, comme de nos jours; et si des actions volcaniques, une elevation du terrain, et des tremblements de terre ont mis au jour des

egress to the primitive mountains, which accordingly form chains in the direction prescribed to them by the fissure. We may therefore look for a greater development of volcanic agencies at the bottom of such fissures than on the highlands.

Fossil salt, according to the most recent researches, is a product of volcanic or plutonic action along an opening of this description. That springs of asphaltum or bitumen, however, originate in the same manner, is proved by the number of them which exist in the tract of country extending from the foot of the Zagrus in the neighborbood of Bassora as far as Mosul, and at Bakou, by the one in the bay of Naples and at Melliti near Syracuse, and also by those of Zante; to which may be added the bitumen of Seyssel, of which the foot-paths of Paris are constructed.

The asphaltum of the Dead Sea is probably nothing more than the bitumen consolidated at the bottom of the lake, which being unable to flow off, forms there a bed, as is the case in the island of Trinidad. It is altogether probable that this accumulation took place in ancient times as in our own day; and if volcanic actions, the upheaving of the soil, and earthquakes, have brought to light, masses of asphaltum analogous

masses d'asphalte analogues à celles que vous avez decrite (phénomène de la plus haute importance, inconnue jusqu'ici,) on peut très bien concevoir la conflagration de cités entières l'inflammation de matières si éminément combustibles. Si on pouvait decouvrir quelque masse basaltique dans la partie ou méridionale ou vers l'extremité sud de la Mer Morte, on pouvait croire, qu'un "dyke" basaltique se soit fait jour lors de la celebre catastrophe, comme cela est arrivé en 1820 près de l'isle de Banda et au pied du volcan de Ternate, (Descript. Phys. des Isles Banains. p. 412.) Les mouvements qui accompagnent la sortie d'un tel" dyke" sont bien en état de produire tous les phénomènes qui ont changé cette contrée interressante, sans éxercer une influence très marquée sur la forme et la configuration des montagnes à l'entour.

La fertilité du sel dépend quelquefois de très légers accidents. Il n'est pas probable que le bitume soit propre pours l'augmenter. Mais il est bien possible, que les mouvements du terrain ont pu mettre au jour une plus grande masse de sel gemme, entrainée par les eaux vers le fond de la vallée; ce qui suffisait pour lui ôter sa productibilité. Le sel gemme n'aurait pas tant frappé Lot, pour l'imaginer que sa femme eut été changée en sel, si l'on avait eu con

to those you have described (a phenomenon of the highest importance and hitherto unknown), we can easily conceive the conflagration of entire cities in consequence of the taking fire of materials so excessively combustible.

If a mass of basalt could be discovered in the southern part or towards the southern extremity of the Dead Sea, we might suppose that a basaltic dyke had made its appearance at the celebrated catastrophe, as occurred in 1820 near the island of Banda and also at the foot of the volcano of Ternati. The movements attending the eruption of such a dyke would be well calculated to produce all the phenomena which have changed the face of this interesting country, without exercising a very marked influence on the figure and conformation of the surrounding mountains.

The fertility of the soil sometimes depends on very trifling circumstances. It is not probable that bitumen is calculated to augment it; but it is very possible that the movements of the earth may have expelled a greater mass of fossil salt, afterwards drawn by the water towards the bottom of the valley, which would suffice to destroy its productiveness. The fossil salt would not so have struck Lot as to make him SECOND SERIES, VOL. III. NO. I.

5

naissance de son existence entre les couches de la montagne avant le catastrophe mémorable.

Il faut espérer que la Societé Géologique de Londres, si active, voudra hien un jour envoyer un de ses membres pour éclairer avec le flambeau de la Géologie des faits qui intéressent tout le monde. Mais il faudrait rechercher toute la constitution géologique et du Liban et de toute la vallée du Jourdain depuis Tiberias jusqu'à Akaba.

Je conçois, Monsieur, que tout ceci doit peu vous contenter. Mais je pense qu'il est témeraire de se faire une théorie sur des faits dont on n'a pas du moins observé soimême les résultats.

J'ai l'honneur d'être avec la plus haute consideration,
Monsieur,

(Signé :)

votre tres humble et obeissant, LEOPOLD DE BUCH.

III. Extract from the Work: Description des Isles Canaries etc. par L. de Buch. P. 412. Paris, 1836.*

L'isle de Banda avait auparavant une grande baie sur la côte occidentale: en 1820, après que l'eruption se fut terminée, il se fit dans la mer un soulèvement; et une masse solide,

imagine that his wife had been turned into salt, if its existence between the strata of the mountains had been known previous to the memorable catastrophe.

It is to be hoped that the Geological Society of London, which is so active in its exertions, will one day send one of its members to illuminate with the torch of geology facts that are interesting to all the world. In so doing it would be necessary to investigate the geological structure of the Libanus and of the entire valley of the Jordan from Tiberias to Akaba.

I suspect, sir, that this will prove to you far from satisfactory; but I consider it rash to form a theory on facts of which one has not been able at least to observe for one's self the results. I have the honor to be, &c., LEOPOLD DE BUCH.

(Signed,)

• Translation.

The island of Banda had formerly a large bay on its eastern side. In 1820, when the eruption was at an end, the sea became agitated, and there arose a solid mass composed of large blocks

composée de gros blocs semblables à du basalte, vint non seulement remplir et combler cette baie dont la profondeur etait 60 brasses mais elle forma même, au dessus de la mer, des collines très élevées et fort étendues, qui entourent le pied du volcan, et s'appuient contre les flancs de cette montagne.

Aucune des matieres qui composent cette masse soulevée, n'a été fondue ou coulante; tous les blocs étaient crevassés, et degageaient d'abondantes vapeurs, mais ce soulèvement n'a rejeté ni rapilles, ni cendres, ni pierre-ponces. Les habitants de Banda, dont les maisons se trouvent sur le revers opposé, ne s'aperçurent de ce phénomène remarquable, qu'après que la plus grande partie de ce soulèvement se fut effectué, et lorsqu'ils en eurent été avertis par les vapeurs et par l'echauffement des eaux de la mer. Lorsque M. Reinwardts visita et examina cette localité en 1821, des vapeurs d'eau et de souffre se degageaient encore entre ces blocs entassés. Le môle élevé au milieu de la baie, est formé de couches très épaisses, qui sont inclinés des deux cotés, et dont le milieu au cime est recourbée en dôme. Les couches inferieures sont tout-a-fait compactés; les couches superieures, au contraire, sont poreuses (Boon-mesch, p. 88,) Il semble que ce soit la répétition des effects du soulèvement

resembling basalt, that not only filled up this bay, whose depth was sixty fathoms, but also formed above the level of the sea very high and extensive hills, which surround the base of the volcano, and rest against the sides of this mountain.

None of the substances composing this elevated mass were in a fluid state. All the blocks contained fissures and disengaged vapors in abundance; but the eruption threw out neither rapils, cinders, nor pumice-stones. The inhabitants of Banda, whose dwellings are situated on the opposite side, did not perceive this phenomenon until the greater part of the eruption had been completed, when they became apprised of it by the vapors and the warmth of the sea-water. When Mr. Reinwardts visited and examined the locality, in 1831, steam and sulphurous vapours were still thrown off from the coacervated blocks. The mole raised in the middle of the bay is formed of very thick strata, sloping down to either shore and rounded at the summit in the form of a dome. The lower strata are extremely compact, while the upper ones on the contrary are porous. This appears to be a further effect of the raising of the cone itself of a volcano; from which occurrence one may

du cône même d'un volcan, et par cet évenément on peut se faire une idée de la possibilité de l'elévation des grandes masses solides qui ont produit les obélisques d' Auvergne, et les murs basaltiques saillants qui terminent les filons de basalte.

IV. Extract from a Paper on " the Pitch Lake of the Island of Trinidad," by N. Nugent, M. D., Transactions of the Royal Geological Society, London, 1811, vol. 1. p. 63.

Being desirous to visit the celebrated Lake of Pitch, previously to my departure from the Island of Trinidad, I embarked with that intention in the month of October, 1807, in a small vessel at Port Spain. After a pleasant sail of about thirty miles down the Gulph of Paria, we arrived at the point la Braye, so called by the French from its characteristic feature. It is a considerable headland, about eighty feet above the level of the sea, and perhaps two miles long and two broad. We landed on the southern side of the point, at the plantation of Mr. Vessigny. We ascended the hill, which was entirely composed of porcelain-jasper rock, to the plantation, where we procured a negro guide, who conducted us through a wood about three quarters of a mile. We now perceived a strong sulphurous and pitchy smell, like that of burning coal, and soon after had a view of the lake, which at first sight appeared to be an expanse of still water, frequently interrupted by clumps of dwarf trees or islets of rushes and shrubs; but on a nearer approach we found it to be in reality an extensive plain of mineral pitch, with frequent crevices and chasms filled with water. The singularity of the scene was altogether so great, that it was some time before I could recover from my surprise so as to investigate it minutely. The surface of the lake is of the color of ashes, and at this season was not polished or smooth so as to be slippery; the hardness or consistence was such as to bear any weight, and it was not adhesive, though it partially received the impression of the foot; it bore us

form an idea of the possibility of the elevation of the great solid masses that have produced the obelisks of Auvergne and of the projecting walls of basalt terminating the veins of that substance,