The Top Of The Imposible, As Nearly As I Could Perceive, Is Covered With A Quartzose Sandstone, Free From Petrifactions.

Here, as on the ridge of the neighbouring mountains, the strata pretty regularly take the direction from north-north-east to south-south-west.

This direction is also most common in the primitive formations in the peninsula of Araya, and along the coasts of Venezuela. On the northern declivity of the Imposible, near the Penas Negras, an abundant spring issues from sandstone, which alternates with a schistose clay. We remarked on this point fractured strata, which lie from north-west to south-east, and the dip of which is almost perpendicular.

The Llaneros, or inhabitants of the plains, send their produce, especially maize, leather, and cattle, to the port of Cumana by the road over the Imposible. We continually saw mules arrive, driven by Indians or mulattoes. Several parts of the vast forests which surround the mountain, had taken fire. Reddish flames, half enveloped in clouds of smoke, presented a very grand spectacle. The inhabitants set fire to the forests, to improve the pasturage, and to destroy the shrubs that choke the grass. Enormous conflagrations, too, are often caused by the carelessness of the Indians, who neglect, when they travel, to extinguish the fires by which they have dressed their food. These accidents contribute to diminish the number of old trees in the road from Cumana to Cumanacoa; and the inhabitants observe justly, that, in several parts of their province, the dryness has increased, not only because every year the frequency of earthquakes causes more crevices in the soil; but also because it is now less thickly wooded than it was at the time of the conquest.

I arose during the night to determine the latitude of the place by the passage of Fomalhaut over the meridian; but the observation was lost, owing to the time I employed in taking the level of the artificial horizon. It was midnight, and I was benumbed with cold, as were also our guides: yet the thermometer kept at 19.7 degrees. At Cumana I have never seen it sink below 21 degrees; but then the house in which we dwelt on the Imposible was 258 toises above the level of the sea. At the Casa de la Polvora I determined the dip of the magnetic needle, which was 42.5 degrees.* (* The magnetic dip is always measured in this work, according to the centesimal division, if the contrary be not expressly mentioned.) The number of oscillations correspondent to 10 minutes of time was 233. The intensity of the magnetic forces had consequently augmented from the coast to the mountain, perhaps from the influence of some ferruginous matter, hidden in the strata of sandstone which cover the Alpine limestone.

We left the Imposible on the 5th of September before sunrise. The descent is very dangerous for beasts of burden; the path being in general but fifteen inches broad, and bordered by precipices. In descending the mountain, we observed the rock of Alpine limestone reappearing under the sandstone.

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