Mobil Oil test well 22-19-g, Tip Top Unit (Carboniferous of the United States)

Also known as Sando et al. Tip Top Loc.71

Where: Sublette County, Wyoming (42.4° N, 110.3° W: paleocoordinates 4.4° N, 37.4° W)

• coordinate estimated from map

• small collection-level geographic resolution

When: Ranchester Member (Amsden Formation), Atokan (318.1 - 311.4 Ma)

• Limestone 30-55 ft below top of Amsden Fm. "Pennsylvanian (Atokan)."

• bed-level stratigraphic resolution

Environment/lithology: offshore shelf; lithified, lenticular, concretionary, gray, yellow, sandy, cherty/siliceous dolomite and green, red shale

• ranchester: heterogenous sequence of interbedded cherty dolomite and limestone, sandstone, and shale. carbonate rocks predominate; thin- to thick-bedded, fine grained to coarsely crystalling, yellowish-gray weathering dolomite and dolomitic limestone are generally much more abundant than thin-bedded, fine- to medium-grained, light-gray to purple weathering limestone. carbonate beds, particularly dolomites, contain abundant gray, brown or jasperoid chert in small nodules, irregular lenses and irregular networks. red and green shale in thin beds and partings are commonly interbedded with the carbonate rocks, particularly in the upper half, and may compose significant thicknesses of the member at some localities. thin beds of fine- to medium-grained, white to pink sandstone occur throughout the member but are most abundant in the upper half. quartz sand is also a minor constituent of some of the carbonate beds. anhydrite was reported as a minor constituent of some dolomite beds.

Collection methods: core,

• "Fossils listed by Marzolf, 1965, p.4."

Primary reference: W. J. Sando, M. Gordon, Jr., and J. T. Dutro. 1975. Stratigraphy and geologic history of the Amsden Formation (Mississippian and Pennsylvanian) of Wyoming. United States Geological Survey Professional Paper 848A:1-83 [J. Alroy/M. Sommers/M. Uhen]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 5734: authorized by John Alroy, entered by Mike Sommers on 17.11.1999

Creative Commons license: CC BY (attribution)

Taxonomic list

 Archaediscacea - Archaediscidae
 Fusulinoidea - Eostaffellidae
 Earlandiacea - Tuberitinidae
 Earlandiacea - Pseudoammodiscidae
 Endothyroidea - Bradyinidae
 Endothyroidea - Endothyridae
 Palaeotextularoidea - Biseriamminidae
Lipinella sp.
(nom. nud.)
 Palaeotextularoidea - Palaeotextulariidae
 Miliolida - Cornuspiridae