I Say Apparent Dryness, For My Hygrometric Observations Prove That The Atmosphere Of Cumana And Araya Contains Nearly Nine-Tenths Of The Quantity Of Watery Vapour Necessary To Its Perfect Saturation.

It is this air, at once hot and humid, that nourishes those vegetable reservoirs, the cucurbitaceous plants, the agaves and melocactuses half-buried in the sand.

When we visited the peninsula the preceding year there was a great scarcity of water; the goats for want of grass died by hundreds. During our stay at the Orinoco the order of the seasons seemed to be entirely changed. At Araya, Cochen, and even in the island of Margareta it had rained abundantly; and those showers were remembered by the inhabitants in the same way as a fall of aerolites would be noted in the recollection of the naturalists of Europe.

The Indian who was our guide scarcely knew in what direction we should find the alum; he was ignorant of its real position. This ignorance of localities characterises almost all the guides here, who are chosen from among the most indolent class of the people. We wandered for eight or nine hours among rocks totally bare of vegetation. The mica-slate passes sometimes to clay-slate of a darkish grey. I was again struck by the extreme regularity in the direction and inclination of the strata. They run north 50 degrees east, inclining from 60 to 70 degrees north-west. This is the general direction which I had observed in the gneiss-granite of Caracas and the Orinoco, in the hornblende-slates of Angostura, and even in the greater part of the secondary rocks we had just examined. The beds, over a vast extent of land, make the same angle with the meridian of the place; they present a parallelism, which may be considered as one of the great geologic laws capable of being verified by precise measures. Advancing toward Cape Chuparuparu, the veins of quartz that cross the mica-slate increase in size. We found some from one to two toises broad, full of small fasciculated crystals of rutile titanite. We sought in vain for cyanite, which we had discovered in some blocks near Maniquarez. Farther on the mica-state presents not veins, but little beds of graphite or carburetted iron. They are from two to three inches thick and have precisely the same direction and inclination as the rock. Graphite, in primitive soils, marks the first appearance of carbon on the globe - that of carbon uncombined with hydrogen. It is anterior to the period when the surface of the earth became covered with monocotyledonous plants. From the summit of those wild mountains there is a majestic view of the island of Margareta. Two groups of mountains already mentioned, those of Macanao and La Vega de San Juan, rise from the bosom of the waters. The capital of the island, La Asuncion, the port of Pampatar, and the villages of Pueblo de la Mar, Pueblo del Norte and San Juan belong to the second and most easterly of these groups. The western group, the Macanao, is almost entirely uninhabited. The isthmus that divides these large masses of mica-slate was scarcely visible; its form appeared changed by the effect of the mirage and we recognized the intermediate part, through which runs the Laguna Grande, only by two small hills of a sugarloaf form, in the meridian of the Punta de Piedras. Nearer we look down on the small desert archipelago of the four Morros del Tunal, the Caribbee and the Lobos Islands.

After much vain search we at length found, before we descended to the northern coast of the peninsula of Araya, in a ravine of very difficult access (Aroyo del Robalo), the mineral which had been shown to us at Cumana. The mica-slate changed suddenly into carburetted and shining clay-slate. It was an ampelite; and the waters (for there are small springs in those parts, and some have recently been discovered near the village of Maniquarez) were impregnated with yellow oxide of iron and had a styptic taste. We found the sides of the neighbouring rocks lined with capillary sulphate of alumina in effervescence; and real beds, two inches thick, full of native alum, extending as far as the eye could reach in the clay slate. The alum is greyish white, somewhat dull on the surface and of an almost glassy lustre internally. Its fracture is not fibrous but imperfectly conchoidal. It is slightly translucent when its fragments are thin; and has a sweetish and astringent taste without any bitter mixture. When on the spot, I proposed to myself the question whether this alum, so pure, and filling beds in the clay-slate without leaving the smallest void, be of a formation contemporary with the rock, or whether it be of a recent, and in some sort secondary, origin, like the muriate of soda, found sometimes in small veins, where strongly concentrated springs traverse beds of gypsum or clay. In these parts nothing seems to indicate a process of formation likely to be renewed in our days. The slaty rock exhibits no open cleft; and none is found parallel with the direction of the slates. It may also be inquired whether this aluminous slate be a transition-formation lying on the primitive mica-slate of Araya, or whether it owe its origin merely to a change of composition and texture in the beds of mica-slate. I lean to the latter proposition; for the transition is progressive, and the clay-slate (thonschiefer) and mica-slate appear to me to constitute here but one formation. The presence of cyanite, rutile-titanite, and garnets, and the absence of Lydian stone, and all fragmentary or arenaceous rocks, seem to characterise the formation we describe as primitive. It is asserted that even in Europe ampelite and green stone are found, though rarely, in slates anterior to transition-slate.

When, in 1785, after an earthquake, a great rocky mass was broken off in the Aroyo del Robalo, the Guaykeries of Los Serritos collected fragments of alum five or six inches in diameter, extremely pure and transparent.

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