RECONNAISSANCE GEOLOGY AND VERTEBRATE PALEONTOLOGY OF EL SALVADOR, CENTRAL AMERICA
The surface rocks in El Slavador consist primarily of ? Pliocene, early Pleistocene, late Pleistocene, and recent volcanics. In the Metapan area are exposures of ?pre-Mesozoic monzonite, the lower and middle Jurassic continental Metapan beds, and Cretaceous marine limestone, overlain unconformably by late Tertiary volcanics and continental sediment. The Tertiary is represented by a poorly consolidated sandstone and conglomerate approximately 650 feet thick, which overlies with unconformity 30 feet of gray andesite. The Mesozoic includes 400 feet of early Cretaceous limestone, underlain with apparent conformity by the Metapan beds, consisting of 180 feet of red and brown calcareous shale, 30 feet of hard vein quartz pebble conglomerate, and 75+ feet of interbedded fine-grained green sandstone and red, brown, and green shales. No identifiable vertebrate remains older than Pleistocene were found in El Salvador, though some of the beds referred to ?Pliocene or early Pleistocene may eventually yield late Pliocene fossils. Fossils have been found in 20 localities in 8 of the 14 departments in the country. The best locality was the Hormiguero quarry where a large series of Megatherium remains were uncovered. These ground sloths had been trapped and mired in a boghole. Other mammals found in the quarry were Smilodon, Bison, toxodont, and a small camelid. Mammuthus (mammoth) and Cuvieronius (spiral-tusked mastodon) were found at other localities. This probably is near the southernmost range of the mammoth and possibly near the northern limit for the South American toxodonts. Some poorly preserved fish and leaves, probably late Pleistocene, were found in barranca El Sisimico near San Vicente.