- Usage in publication:
-
- Toa Vaca formation
- Modifications:
-
- Named
- Dominant lithology:
-
- Tuff
- Breccia
- Andesite
- Mudstone
- Sandstone
Summary:
Named for Rio Toa Vaca, Puerto Rico. Toa Vaca Formation composed of 90 percent tuff breccia, 5 percent andesite flows, and 5 percent tuffaceous mudstones and sandstones. Thickness cannot be calculated. Overlies Ildefonso formation; unconformably underlies Eocene Jacaguas group. Includes Rio Jueyes and Guayama series of Hodge (1920). Unit is of Late Cretaceous (Santonian) 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 ([ ]).