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National Geologic Map Database

Geologic Unit: Millsap Lake

Usage:

Millsap Lake Formation of Strawn Group (TX*)
Millsap Lake Formation of Deese Group (OK*)
Millsap Lake Group (TX)
Called †Millsap in early reports.


Subunits:

GROUP STATUS (alphabetical) --all in TX: Dickerson Formation, Grindstone Creek Formation, Lazy Bend Formation.
FORMATION STATUS (alphabetical): Brannon Bridge Limestone Member or Brannon Limestone Member (TX), Camp Ground Member (OK), Dennis Bridge Limestone Member (TX), Devils Kitchen Member (OK), Dickerson Member (TX), Dobbs Valley Sandstone Member (TX), Goen Limestone Member (TX), Grindstone Creek Member (TX), Hill Creek Shale Member (TX), Kickapoo Falls Limestone Member (TX), Lazy Bend Member (TX), Meek Bend Limestone Member (TX), Santo Limestone Member (TX), Steussy Shale Member (TX).


Geologic age:

Middle Pennsylvanian*


Type section, locality, area and/or origin of name:

Named from town of Millsap, on Texas and Pacific RR, western part Parker Co., north-central TX, where well developed (Cummins, 1891).
Type locality: Millsap Lake, Parker Co., north-central TX (Sellards, 1933).


AAPG geologic province:

Bend arch*
Fort Worth syncline
South Oklahoma folded belt
Strawn basin


For more information, please contact Nancy Stamm, Geologic Names Committee Secretary.

Asterisk (*) indicates usage by the U.S. Geological Survey. Other usages by state geological surveys.

"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 does not conform with nomenclatural guidelines (CSN, 1933; ACSN, 1961, 1970; NACSN, 1983, 2005). This may be explained within brackets ([ ]).