San Sebastian Formation of Rio Guatemala Group (PR*)
early Tertiary (middle Oligocene)*
Principal outcrop area extends from the Quebrada Collazo, 4 km east of San Sebastian, northwestward to within 4 km of Aguadilla, where outcrops disappear under alluvium of Rio Culebrinas Valley, Aguadilla quadrangle, Puerto Rico (US geologic names lexicon, USGS Bull. 1200).
Caribbean region*
For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.
Asterisk (*) indicates published by U.S. Geological Survey authors.
"No current usage" (†) implies that a name has been abandoned or has fallen into disuse. Former usage and, if known, replacement name given in parentheses ( ).
Slash (/) indicates name conflicts with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005, 2021). May be explained within brackets ([ ]).