CAUS, Formation

TERTIARY (upper Eocene)

State of Trujillo, Venezuela

Author of name: R. A. Liddle, 1928.

Original reference: R. A. Liddle, 1928, p. 238-239.

Original description: ibid.

The name "Río Caús formation" was first used by Liddle (1928, p. 238-239) for a sequence of shales and limestones that outcrop in the Río Caús, near the small village of Mesa de las Pavas, in the southwestern part of the State of Trujillo. Although Liddle (1928, p. 238) described the formation as consisting of only a few feet of thin limestones, M. L. Krueger (1927, private report) described the formation at its type locality, the junction of Río Caús and Quebrada Honda, as consisting of over 260 feet of interbedded, white, calcareous sandstone, thick shale, sandy shale and fossiliferous limestone containing Operculina cooked and Discocyclina.

Salvador (1950) recommended shortening the name to Caús formation and described the unit in northern Trujillo (Chejendé) as consisting of interbedded silty sandstones, silty shales and siltstones, and limonitic sandstones. All lithic types are thin-bedded, calcareous and highly glauconitic. The thickness of the Chejendé area, measured at Fila de la Soledad, is 260 feet (80 meters) similar to that at Río Caús of 266 feet (82 meters). The formation outcrops along the Andean mountain front from northern Mérida to southwestern Lara.

The Caús formation in the Chejendé area is very fossiliferous throughout. Rutsch (Salvador, 1950) identified Raetomya falconensis, Rimella gaudichaudi alauda, and Athleta (Volutospina) ochsei. Operculina cooked and Discocyclina s p. are very abundant. The age has been determined as upper Eocene.

The Caús formation is in transitional stratigraphic contact with the underlying Escuque formation and the overlying Paují formation. The formation is the equivalent, somewhat reduced in thickness, of Tash's "transition beds", the top of his upper Misoa-Trujillo formation (1937, p. 168) and is also apparently the same as Sutton's Lower Paují (1946, p. 1671). The Soledad formation (de Cizancourt, 1951, p. 45) is a local, now obsolete name for the Caús formation.

Gordon A. Young