- GeoRef, Copyright 2004, American Geological Institute. Reference includes data from Bibliography and Index of Geology Exclusive of North America, Geological Society of America, Boulder, CO, United States
"The Oligocene of the Carmen-Zambrano area is divided into five foraminiferal zones and two subzones, the lower Miocene into two zones; the middle Miocene contains one zonule. A gradual filling-in of the basin is suggested, which was interrupted in the Carmen area by deepening of the sea during the upper lower Oligocene and the middle Oligocene, and at the end of the upper Oligocene. The zones are correlated with faunal units from other parts of the Caribbean area. Ten new species and one new variety are described."