USGS Mesozoic D10742, Chispa Summit (Cretaceous of the United States)

Where: Jeff Davis County, Texas (30.7° N, 104.8° W: paleocoordinates 30.9° N, 69.8° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Acanthoceras bellense ammonoid zone, Chispa Summit Formation, Middle Cenomanian (99.6 - 93.5 Ma)

• 4.6 m (15 ft) above base; was Acanthoceras amphibolum zone

• bed-level stratigraphic resolution

Environment/lithology: marine; lithified lithology not reported

Size class: macrofossils

Collected by S.C. Hook, W.A. Cobban in 1979; reposited in the USNM

Primary reference: W. A. Cobban. 1988. Tarrantoceras Stephenson and related ammonoid genera from Cenomanian (Upper Cretaceous) rocks in Texas and the western interior of the United States. United States Geological Survey Professional Paper 1473:1-30 [M. Clapham/M. Clapham]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 177076: authorized by Matthew Clapham, entered by Matthew Clapham on 18.03.2016, edited by Pete Wagner

Creative Commons license: CC BY (attribution)

Taxonomic list

Bivalvia
 Ostreida - Ostreidae
Ostrea beloiti Logan 1899 oyster
 Myalinida - Inoceramidae
Inoceramus aff. arvanus Stephenson 1953 clam
Cephalopoda
 Ammonitida - Turrilitidae
"Turrilites acutus" = Turrilites (Turrilites) acutus
"Turrilites acutus" = Turrilites (Turrilites) acutus Passy 1832 ammonite
 Ammonitida - Acanthoceratidae
Tarrantoceras spp. Stephenson 1955 ammonite
"Tarrantoceras sellardsi" = Tarrantoceras (Tarrantoceras) sellardsi Adkins 1928 ammonite
Cunningtoniceras johnsonanum Stephenson 1955 ammonite
? Acompsoceras sp. Hyatt 1903 ammonite
""Eucalycoceras" leonense" = Calycoceras (Gentoniceras) leonense Adkins 1928 ammonite