Usage:
Hely Member of Hager Limestone of Plattin Group (MO)
Hely Member of Grand Detour Formation of Platteville Group (IL)
Geologic age:
Late Ordovician (Mohawkian; Turinian)
Type section, locality, area and/or origin of name:
Type section: Hely's upper quarry and adjoining Federal and Marquette quarries, southern outskirts of Cape Girardeau, in NW/4 NE/4 and SE/4 NW/4 sec. 18, T. 30 N., R. 14 E., [approx. Lat. 37 deg. 16 min. 18 sec. N., Long. 89 deg. 32 min. 14 sec. W., Cape Girardeau 7.5-min quadrangle], Cape Girardeau Co., southeastern MO (Templeton and Willman, 1963, Illinois Geol. Survey Bull., no. 89, p. 86; Willman and Buschbach, 1975, Illinois Geol. Survey Bull., no. 95, p. 47-87).
Named from Hely's upper quarry (Templeton and Willman, 1963, p. 86; Willman and Buschbach, 1975).
Notable exposures in Dixon-Oregon area, northern IL (Templeton and Willman, 1952).
AAPG geologic province:
Illinois basin
Ozark uplift
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 ([ ]).