Mill Creek, White River junction, USGS 8354 (Carboniferous of the United States)

Also known as Locality H 8; Henbest and Henbest, Nov. 17, 1936

Where: Washington County, Arkansas (35.9° N, 94.2° W: paleocoordinates 8.7° S, 31.8° W)

• coordinate stated in text

• small collection-level geographic resolution

When: Prairie Grove Member (Hale Formation), Morrowan (323.2 - 318.6 Ma)

• The type locality of the Hale formation is Hale Mountain in wester Washington County where it is relatively thick. Recent work has shown that two mappable members, the Cane Hill below and the Prairie Grove member above, can be recognized in Washington County.

•The Cane Hill member is as much as 65 feet in thickness and is composed largely of silt, silty sandstone, and fine-grained sandstone; locally there are beds of fossiliferous crossbedded limestone in the lower part.

•In the Harrison quadrangle, in Carroll and Boone Counties, the Hale formation as mapped by Purdue and Miser (1916) is overlain by the Atoka formation and contains a considerable amount of shale, particularly the lower part, which may either represent the Cane Hill member, or include the Imo formation and upper shale member of the Pitkin limestone, or parts of all three.

•The two members of the Hale formation can be recognized in Washington and Madison Counties, as well as in adjacent parts of Crawford County. In this region the Cane Hill member rests unconformably on the Pitkin limestone, or on the Fayetteville shale where the Pitkin has been cut out by erosion prior to Morrow deposition. The Prarie Grove member is overlain conformmably by the Bloyd shale.

• group of beds-level stratigraphic resolution

Environment/lithology: shallow subtidal; lithified, shelly/skeletal limestone and lithified, fine-grained, medium, calcareous sandstone

• The Prairie Grove member,...,ranges in thickness from 600 to 200 feet and is composed almost entirely of fine- to medium-grained calcareous sandstone, commonly lamellar crossbedded or a honeycomb structure emphasized differentially on weathered surfaces. Lenses of fossiliferous, crinoidal, and oolitic limestone are rather common in the upper and, locally, in the lower parts. At some places Henbest (1953, p.1940,1941) has noted a basal conglomerate commonly made of pebbles and cobbles of quartzitic sandstone. This unit is quite fossiliferous, particularly where the limestone content is high and cephalopods are fairly common locally.

Size class: macrofossils

Reposited in the USGS

Primary reference: M. Gordon. 1964. Carboniferous Cephalopods of Arkansas. United States Geological Survey Professional Paper 460:1-322 [J. Alroy/C. Simpson/M. Clapham]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 43382: authorized by John Alroy, entered by Carl Simpson on 12.08.2004

Creative Commons license: CC BY (attribution)

Taxonomic list

Cephalopoda
 Goniatitida - Bisatoceratidae
Bisatoceras secundum Miller and Moore 1938 ammonite
 Goniatitida - Reticuloceratidae
"Gastrioceras henbesti" = Quinnites henbesti, "Gastrioceras textum" = Quinnites textum, "Pygmaeoceras pygmaeum" = Verneuilites pygmaeus
"Gastrioceras henbesti" = Quinnites henbesti Gordon 1964 ammonite
"Gastrioceras textum" = Quinnites textum Gordon 1964 ammonite
"Pygmaeoceras pygmaeum" = Verneuilites pygmaeus Mather 1915 ammonite
 Goniatitida - Glaphyritidae
"Glaphyrites oblatus" = Syngastrioceras oblatum
"Glaphyrites oblatus" = Syngastrioceras oblatum Miller and Moore 1938 ammonite
 Pseudorthocerida - Pseudorthoceratidae
"Pseudorthoceras knoxense" = Pseudorthoceras knoxense, "Mooreoceras normale" = Pseudorthoceras knoxense
"Pseudorthoceras knoxense" = Pseudorthoceras knoxense McChesney 1859
"Mooreoceras normale" = Pseudorthoceras knoxense McChesney 1859