Usage:
Hartley Augen Gneiss (MD*,PA*)
Hartley Member of Baltimore Gneiss (MD)
Geologic age:
Precambrian*
Type section, locality, area and/or origin of name:
Outcrops at Hartley Mill on Long Green Creek, eastern Baltimore Co., MD (Knopf and Jonas, 1923).
AAPG geologic province:
Piedmont-Blue Ridge province*
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 ([ ]).