- Usage in publication:
-
- Bay of Pillars Formation*
- Modifications:
-
- Original reference
- Dominant lithology:
-
- Sandstone
- Argillite
- AAPG geologic province:
-
- Alaska Southeastern region
Summary:
Pg. C6-C11, pls. Bay of Pillars Formation. Name applied to thick sequence of complexly folded calcareous sandstone and argillite that underlies most of northwestern part of Kuiu Island. Primarily medium-grained medium-light-gray calcareous lithic sandstone. Owing to complex deformation, thickness of formation unknown but probably several thousarid feet. Underlies Kuiu Formation (new). In northwestern most part of island, intruded by gabbro and, adamellite plutons of Cretaceous(?) age. Is at least in part Late Silurian age based on graptolites identified by W.B.N. Berry (written commun., 1964).
Type locality: north of shoreline of Bay of Pillars, Kuiu Island, southeastern AK.
Source: US geologic names lexicon (USGS Bull. 1350, p. 50); supplemental information from GNU records (USGS DDS-6; Menlo GNULEX).
- Usage in publication:
-
- Bay of Pillars Formation*
- Modifications:
-
- Age modified
- Biostratigraphic dating
- Areal extent
- AAPG geologic province:
-
- Alaska Southeastern region
Summary:
Bay of Pillars Formation in Afflech Canal has yielded graptolites of both latest Early Silurian and Late Silurian age. Tongues of graptolite-bearing Bay of Pillars Formation occur within Heceta Limestone in Shipley Bay on northernmost Prince of Wales Island.
Source: GNU records (USGS DDS-6; Menlo 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 ([ ]).