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National Geologic Map Database

Geologic Unit: Blach Ranch

Usage:

Blach Ranch Limestone [unranked] in Cisco Group (TX)
Blach Ranch Limestone Member of Thrifty Formation of Cisco Group (TX*)


Geologic age:

Late Pennsylvanian (Virgilian)*


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

Type section (redescribed): on original Blach Brothers Ranch, now two ranches owned by heirs Jack and Bill Black and B.H. Trammell of Breckenridge. Type section is 3.75 mi east of Crystal Falls, northeast of Breckenridge in north-central Stephens Co., central northern TX. Ranch name was misspelled in original description. Limestone crops out in north-south belt across Black and Trammell Ranches. New Type section is in and near RR cut on Chicago, Rock Island, and Pacific RR (Plummer and Moore, 1922; Brown, 1960).


AAPG geologic province:

Bend arch*
Fort Worth syncline


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 ([ ]).