Usage:
Nasset Bentonite Bed of Sherwood Member of Dunleith Formation of Galena Group (IL,IA)
Nasset Bentonite Bed of Loves Park Member of Dunleith Formation of Galena Group (IL)
Geologic age:
Late Ordovician (Mohawkian; Chatfieldian)
Type section, locality, area and/or origin of name:
Type section: Engineers Old Cut section, stream diversion channel, 2.4 km west of Decorah, in SE/4 NE/4 sec. 18, T. 98 N., R. 8 W., [approx. Lat. 43 deg. 18 min. 24 sec. N., Long. 91 deg. 49 min. 32 sec. W., Decorah 7.5-min quadrangle], Winneshiek Co., northeast IA (Willman and Kolata, 1978).
Named from town of Nasset [no longer exists], 12.8 km east of type section, [approx. Lat. 43 deg. 17 min. 06 sec. N., Long. 91 deg. 40 min. 12 sec. W., Decorah quadrangle (1906 ed.), scale 1:125,000], Winneshiek Co., northeast IA (Willman and Kolata, 1978).
AAPG geologic province:
Iowa shelf
Wisconsin arch
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 ([ ]).