Page:Popular Science Monthly Volume 81.djvu/176

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170
THE POPULAR SCIENCE MONTHLY

TRINIDAD AND BERMUDEZ ASPHALTS AND THEIR USE IN HIGHWAY CONSTRUCTION. II
By CLIFFORD RICHARDSON, M. Am. Soc. C. E.
NEW YORK CITY

The Bermudez Asphalt Deposit

From the mouth of the Orinoco, the northeastern coast of Venezuela, which faces Trinidad, is low and consists of vast mangrove swamps, through which run deep tidal estuaries. That portion forming part of the State of Bermudez extends inland for many miles. It lies on the opposite side of the Gulf of Paria from Trinidad. About 30 miles in an air line from the coast the asphalt deposit, known as the Bermudez pitch lake, is found at the point where a northern range of foothills comes down to the swamp. The Guanaco River, a branch of the San Juan, one of the large cahos or estuaries of this region, at about sixty-five miles, in its winding course, from its mouth, runs within three miles of the deposit, but it is five or six miles to a suitable wharfage site. On the other hand, towards the north, a road runs to the hills and to the village of Guaryquen. These are the means of communication with the deposit. The so-called lake is situated between the edge of the swamp and the foothills in what might be termed a savanna. It is an irregular-shaped surface with a width of about a mile and a half from north to south and about a mile east and west. Its area is a little more than 900 acres, and it is covered with vegetation, high rank grass and shrubs, one to eight feet high, with groves of large moriche palms, called morichales. One sees no dark expanse of pitch on approaching it as at the Trinidad pitch lake, and except at certain points where soft pitch is welling up, nothing of the kind can be found. The level of the surface of the deposit does not vary more than two feet and is largely the same as that of the surrounding swamps. In the rainy season it is mostly flooded and at all times very wet, so that any excavation will fill up with water. . These conditions make it difficult to get about upon it or to excavate pitch easily.

It is readily seen that this deposit is a very different one from that in the pitch lake of Trinidad. It seems to be in fact merely an overflow of soft pitch from several springs, over this large expanse of savanna, and one which has not the depth or uniformity of that at Trinidad.

At different points there is at most a depth of 7 feet of material,