Usage:
Idlewild Member of Lithograph City Formation of Cedar Valley Group (IA)
Geologic age:
early Late Devonian (Frasnian)
Type section, locality, area and/or origin of name:
Floyd quarry, on Cedar River, 2.3 km downstream from Idlewild State Park, in SW/4 SW/4 SE/4 sec. 9, T. 96 N., R. 16 W., Floyd Co., IA (Bunker and others, 1986; Witzke and others, 1988).
AAPG geologic province:
Iowa shelf
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 ([ ]).