Topographic, bathymetric, subsurface, and surface geologic data compiled for the Mosquitia region of the Honduras and Nicaragua Caribbean coast between 13°40^prime to 15°40^primeN lat. and 81°00^prime to 85°30^primeW long. provide important new information on the structural geology of the Colon and Mocoron Mountains along the Patuca River in Honduras and make possible some correlation between onshore and offshore structure.

Information from two petroleum test wells drilled near the coast in Honduras and four drilled along the Nicaraguan coast indicates that the Mosquitia basin is one of the largest sedimentary basins in Central America and includes an area more than 62,500 sq mi. A deep well off the coast of Nicaragua proved the existence of at least 15,000 ft of Tertiary sediments in the basin. Onshore the Mesozoic section is more than 7,000 ft thick.

The framework of the basin was controlled by the Nuclear foreland of Honduras, a hinterland region along the Honduras-Nicaragua border, and a Nicaraguan foreland which may have existed in eastern Nicaragua and offshore near Islas San Andres and Providencia.

The Mesozoic axis of deposition was between the Patuca and Coco Rivers in Honduras. The Coco River ridge (originally a Paleozoic hinterland area) was rejuvenated at the end of the Laramide orogeny and split the Mesozoic basin into two Tertiary basins, one on either side of the ridge. The Coco River ridge extends to the Mosquitia Banks and across the Caribbean Sea to Jamaica as the Nicaragua Rise. The rise is a topographic link in the transverse belt that joins Nuclear Central America to the Greater Antilles.

Several fault patterns onshore can be extended offshore. The main fault trend is northeast-southwest and parallels the Coco River ridge.

The map, although of reconnaissance nature, should provide a basis for future detailed work in the Mosquitia region.