I
mention these situations of asphaltum on account of the remarkable
circumstances peculiar to them in these regions; for I am not
unaware that naphtha, petroleum, and asphaltum are found equally in
volcanic and secondary regions,* and even more frequently in the
latter. (* The inflammable emanations of Pietra Mala, (consisting
of hydrogen gas containing naphtha in a state of suspension) issue
from the Alpine limestone, which may be traced from Covigliano to
Raticofa, and which lies on ancient sandstone near Scarica l'Asino.
Under this sandstone (old red sandstone) we find black transition
limestone and the grauwack (quartzose psammite) of Florence.)
Petroleum is found floating on the sea thirty leagues north of
Trinidad, around the island of Grenada, which contains an
extinguished crater and basalts.
2. Hot Springs of Irapa, at the north-eastern extremity of New
Andalusia, between Rio Caribe, Soro, and Yaguarapayo.
3. Air-volcano, or Salce, of Cumacatar, to the south of San Jose
and Carupano, near the northern coast of the continent, between La
Montana de Paria and the town of Cariaco. Almost constant
explosions are felt in a clayey soil, which is affirmed to be
impregnated with sulphur. Hot sulphureous waters gush out with such
violence that the ground is agitated by very sensible shocks. It is
said that flames have been frequently seen issuing out since the
great earthquake of 1797. These facts are well worthy of being
examined.
4. Petroleum-spring of the Buen Pastor, near Rio Areo. Large masses
of sulphur have been found in clayey soils at Guayuta, as in the
valley of San Bonifacio, and near the junction of the Rio Pao with
the Orinoco.
5. The Hot Waters (Aguas Calientes) south of the Rio Azul, and the
Hollow Ground of Cariaco, which, at the time of the great
earthquake of Cumana, threw up sulphuretted water and viscous
petroleum.
6. Hot waters of the gulf of Cariaco.
7. Petroleum-spring in the same gulf, near Maniquarez. It issues
from mica-slate.
8. Flames issuing from the earth, near Cumana, on the banks of the
Manzanares, and at Mariguitar, on the southern coast of the gulf of
Cariaco, at the time of the great earthquake of 1797.
9. Igneous phenomena of the mountain of Cuchivano, near Cumanacoa.
10. Petroleum-spring gushing from a shoal to the north of the
Caracas Islands. The smell of this spring warns ships of the danger
of this shoal, on which there is only one fathom of water.
11. Thermal springs of the mountain of the Brigantine, near Nueva
Barcelona. Temperature 43.2 degrees (centigrade).
12.
