Marine Eocene Deposits on the East Slope of the Venezuelan Andes

Abstract

Dr. N. H. Darton, of the United States Geological Survey, recently collected on the east slope of the Venezuelan Andes specimens of a dark-colored partly crystalline limestone that carries Foraminifera of Eocene age. This material was collected half a mile southeast of the village of Masparito, or about 12 miles east of Calderas, in the state of Zamora (U. S. Geol. Survey locality 1/1189). On Jahn's geologic map of Venezuela this locality would fall almost due north of Barinas near the eastern edge of the area mapped as schist and gneiss. This Eocene limestone is a thin bed lying near the base of a thick series of shales overlying a quartzite. Additional float material was collected on Rio Arana, west of Calderas. The collection of float limestone also contains specimens of a dark-colored Carboniferous Productus-bearing limestone that in gross features is surprisingly similar to the Eocene limestone. So far as known, this record, which is made available through the kindness of Dr. A. C. Veatch, is the first one of Eocene deposits in the drainage basin of the Orinoco. The float material also establishes the presence of Carboniferous limestone in the Venezuelan Andes. Heretofore, Carboniferous beds have not been reported north of Peru and the Amazon Valley in eastern Brazil.