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National Geologic Map Database

Geologic Unit: San Sebastian

Usage:

San Sebastian Formation of Rio Guatemala Group (PR*)


Geologic age:

early Tertiary (middle Oligocene)*


Type section, locality, area and/or origin of name:

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).


AAPG geologic province:

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 ([ ]).