Chaotic, allochthonous, submarine gravity slide deposits (olistostromes) have been reported with increasing frequency during the past 15 yrs in stratigraphic columns throughout the world. One such unit, estimated to be several hundred meters thick, is distributed over 90 sq km in the Puerto Plata area of north-central Dominican Republic.

The gray, clay-sized, structureless matrix of this unit behaves as a quick-clay under shock, and is composed of kaolinite, quartz, montmorillonite, and illite. Pelagic Foraminifera date the matrix as Paleocene(?) or early Eocene(?).

Exotic blocks within the olistostrome include limestone, serpentinite, andesite, pillow volcanics, and tuffaceous rocks. The longest dimensions of...