They Are The Capparis Tenuisiliqua, Jacq., C. Ferruginea, C. Emarginata, C. Elliptica, C. Reticulata, C. Racemosa.) On Leaving Cumana We

Enjoyed during the short duration of the twilight, from the top of the hill of San Francisco, an extensive view

Over the sea, the plain covered with bera* and its golden flowers (* Palo sano, Zygophyllum arboreum, Jacq. The flowers have the smell of vanilla. It is cultivated in the gardens of the Havannah under the strange name of the dictanno real (royal dittany).), and the mountains of the Brigantine. We were struck by the great proximity in which the Cordillera appeared before the disk of the rising sun had reached the horizon. The tint of the summits is of a deeper blue, their outline is more strongly marked, and their masses are more detached, as long as the transparency of the air is undisturbed by the vapours, which, after accumulating during the night in the valleys, rise in proportion as the atmosphere acquires warmth.

At the hospital of the Divina Pastora the path turns to north-east, and stretches for two leagues over a soil without trees, and formerly levelled by the waters. We there found not only cactuses, tufts of cistus-leaved tribulus, and the beautiful purple euphorbia,* (* Euphorbia tithymaloides.) but also the avicennia, the allionia, the sesuvium, the thalinum, and most of the portulaceous plants which grow on the banks of the gulf of Cariaco. This geographical distribution of plants appears to designate the limits of the ancient coast, and to prove that the hills along the southern side of which we were passing, formed heretofore a small island, separated from the continent by an arm of the sea.

After walking two hours, we arrived at the foot of the high chain of the interior mountains, which stretches from east to west; from the Brigantine to the Cerro de San Lorenzo. There, new rocks appear, and with them another aspect of vegetation. Every object assumes a more majestic and picturesque character; the soil, watered by springs, is furrowed in every direction; trees of gigantic height, covered with lianas, rise from the ravines; their bark, black and burnt by the double action of the light and the oxygen of the atmosphere, contrasts with the fresh verdure of the pothos and dracontium, the tough and shining leaves of which are sometimes several feet long. The parasite monocotyledons take between the tropics the place of the moss and lichens of our northern zone. As we advanced, the forms and grouping of the rocks reminded us of Switzerland and the Tyrol. The heliconia, costus, maranta, and other plants of the family of the balisiers (Canna indica), which near the coasts vegetate only in damp and low places, flourish in the American Alps at considerable height. Thus, by a singular similitude, in the torrid zone, under the influence of an atmosphere continually loaded with vapours the mountain vegetation presents the same features as the vegetation of the marshes in the north of Europe on soil moistened by melting snow.* (* Wahlenberg, de Vegetatione Helvetiae et summi Septentrionis pages 47, 59.)

Before we leave the plains of Cumana, and the breccia, or calcareous sandstone, which constitutes the soil of the seaside, we will describe the different strata of which this very recent formation is composed, as we observed it on the back of the hills that surround the castle of San Antonio.

This breccia, or calcareous sandstone, is a local and partial formation, peculiar to the peninsula of Araya, the coasts of Cumana, and Caracas. We again found it at Cabo Blanco, to the west of the port of Guayra, where it contains, besides broken shells and madrepores, fragments, often angular, of quartz and gneiss. This circumstance assimilates the breccia to that recent sandstone called by the German mineralogists nagelfluhe, which covers so great a part of Switzerland to the height of a thousand toises, without presenting any trace of marine productions. Near Cumana the formation of the calcareous breccia contains: - first, a compact whitish grey limestone, the strata of which, sometimes horizontal, sometimes irregularly inclined, are from five to six inches thick; some beds are almost unmixed with petrifactions, but in the greatest part the cardites, the turbinites, the ostracites, and shells of small dimension, are found so closely connected, that the calcareous matter forms only a cement, by which the grains of quartz and the organized bodies are united: second, a calcareous sandstone, in which the grains of sand are much more frequent than the petrified shells; other strata form a sandstone entirely free from organic fragments, yielding but a small effervescence with acids, and enclosing not lamellae of mica, but nodules of compact brown iron-ore: third, beds of indurated clay containing selenite and lamellar gypsum.

The breccia, or agglomerate of the sea-coast, just described, has a white tint, and it lies immediately on the calcareous formation of Cumanacoa, which is of a bluish grey. These two rocks form a contrast no less striking than the molasse (bur-stone) of the Pays de Vaud, with the calcareous limestone of the Jura. It must be observed, that, by contact of the two formations lying upon each other, the beds of the limestone of Cumanacoa, which I consider as an Alpine limestone, are always largely mixed with clay and marl. Lying, like the mica-slate of Araya, north-east and south-west, they are inclined, near Punta Delgada, under an angle of 60 degrees to south-east.

We traversed the forest by a narrow path, along a rivulet, which rolls foaming over a bed of rocks. We observed, that the vegetation was more brilliant, wherever the Alpine limestone was covered by a quartzose sandstone without petrifactions, and very different from the breccia of the sea-coast. The cause of this phenomenon depends probably not so much on the nature of the ground, as on the greater humidity of the soil. The quartzose sandstone contains thin strata of a blackish clay-slate,* (* Schieferthon.) which might easily be confounded with the secondary thonschiefer; and these strata hinder the water from filtering into the crevices, of which the Alpine limestone is full.

Enter page number Go  Previous Next
Page 89 of 208
Words from 89661 to 90686 of 211363