Personal Narrative Of Travels To The Equinoctial Regions Of America During The Years 1799-1804 - Volume 1 - By Alexander Von Humboldt And Aime Bonpland.
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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.
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