LSJU 2372 (Cretaceous to of the United States)

Where: Merced County, California (36.9° N, 120.8° W: paleocoordinates 43.1° N, 92.0° W)

• coordinate stated in text

When: Moreno Formation (Great Valley Group), Campanian to Campanian (83.6 - 66.0 Ma)

Environment/lithology: marine; medium-grained, calcareous sandstone

• By way of a guess, I would suggest that the good sorting points to marine deposition, the freshness of the material suggests rapid deposition without a great deal of weathering, and the gen- eral mineral assemblage indicates a dominant metamorphic or basic igneous provenance.
• The rock has so much calcite cement that it might be described as a sandy limestone almost as well as· a calcareous sandstone. The quartz and feldspar grains range up to 0.2 mm., and the mica flakes up to 1.0 mm. There is little material in the finer silt grades, the majority of grains being over 0.02 mm. The grains are extremely angular; some of the quartzes show reentrant curves, and some are so elongated as to resemble glass shards.

•The most abundant mineral is quartz, which aggregates about 50 percent of the light minerals. Feldspar (orthoclase 25 percent, plagioclase 25 percent) and a little muscovite make up the remaining light minerals. All varieties of feld- spar are relatively fresh. Heavy minerals are abundant, their relative proportions being ap- proximately as follows:

Size class: macrofossils

Collected by Gary Ellis, R. A. C. Brown, Ivan F. Wilson, and H. G. Hertlein in 1941; reposited in the CAS

Primary reference: H. G. Schenck. 1943. Acila princeps, a new Upper Cretaceous Pelecypod from California. Journal of Paleontology 17(1):60-68 [J. Marcot/J. Marcot]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 206374: authorized by Jonathan Marcot, entered by Jonathan Marcot on 13.11.2019

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Bivalvia
 Arcida - Parallelodontidae
"Parallelodon (Nanovavis) cf. brewerianus" = Nanonavis breweriana
"Parallelodon (Nanovavis) cf. brewerianus" = Nanonavis breweriana Gabb 1864 clam
 Arcida - Glycymerididae
"Glycymeris veatchii" = Glycymerita veatchii
"Glycymeris veatchii" = Glycymerita veatchii Gabb 1864 clam
 Cardiida - Arcticidae
Tenea inflata
Tenea inflata Gabb 1864 clam
 Nuculida - Nuculidae
Acila (Truncacila) princeps n. sp.
Acila (Truncacila) princeps n. sp. Schenck 1943 divaricate nutclam