- Usage in publication:
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- San Juan formation
- Modifications:
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- Named
- Dominant lithology:
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- Sandstone
Summary:
Named San Juan formation of city of San Juan, Puerto Rico. Consists of strongly bedded, cross-bedded, calcareous sandstone. Formation is resistant so that it forms a promontory extending beyond mainland. The unit is probably of sand dune origin and is considered of Pleistocene age.
Source: GNU records (USGS DDS-6; Reston GNULEX).
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 ([ ]).