PBDB Collection

UCLA loc. 3777, North Fork Cottonwood Creek (Cretaceous of the United States)

Also known as LACMIP loc. 23777

Where: Shasta County, California (40.5° N, 122.6° W: paleocoordinates 41.6° N, 82.7° W)

• coordinate based on political unit

• small collection-level geographic resolution

When: Bald Hills Member (Budden Canyon Formation), Early/Lower Cenomanian (99.6 - 93.5 Ma)

• "The Bald Hills Fm. ranges in age from upper Albian through Cenomanian and possibly into lower Turonian." JA: the Bald Hills is actually a member of the Budden Canyon Formation and Lower Cenomanian according to Murphy and Rodda 1996

• bed-level stratigraphic resolution

Environment/lithology: marine; lithified conglomerate

• Congl. grain size from find sand to boulders, avg. 2" diam. Well rounded; matrix med- to coarse-grained graywacke or very sandy mudstone. Majority of cobbles are dark porphyritic volcanics, remainder include metamorphic and granitic rocks, chert, mudstone and limestone. Congl. are sometimes fairly well bedded, esp. near tops, where they almost always grade upward to massive, then finely bedded sandstones.

Size class: macrofossils

Collection methods: mechanical,

Primary reference: M. A. Murphy and P. U. Rodda. 1960. Mollusca of the Cretaceous Bald Hills Formation of California. Journal of Paleontology 34(5):835-858 [J. Alroy/M. Sommers/J. Alroy]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 1787: authorized by John Alroy, entered by Mike Sommers on 08.06.1999, edited by Pete Wagner and Jonathan Marcot

Creative Commons license: CC BY (attribution)

Taxonomic list

• Abundances: R= rare (1-2), U= uncommon (3-10), A= abundant (>10). Authors very unclear as to whether specimens are found in matrix of the conglomerate or within clasts. "Some of the species found in the nodules and other reworked sedimentary rocks were extant at the time this conglomerate unit was deposited." They also list Cucullaea truncata (Gabb) as "...occurs below, above and in the matrix of the conglomerate as well as in the clasts of the conglomerate," then they do not list it in the species list.

Show authors, comments, and common names

Cephalopoda
Ammonitida - Brancoceratidae	Mortoniceras gainesana Mortoniceras gainesana Anderson 1958 ammonite
Ammonitida - Desmoceratidae	Desmoceras (Pseudouhligella) argonauticum¹ Desmoceras (Pseudouhligella) argonauticum¹ Anderson 1958 ammonite (Pseudouhligella) - originally entered as "Desmoceras cf. argonauticum"
Gastropoda
Heterostropha - Ringiculidae	Biplica isoplicata Biplica isoplicata Popenoe 1957 snail quest. ident.
Cerithioidea - Turritellidae	Turritella xylina² Turritella xylina² Squires and Saul 2006 turret shell quest. ident. - originally entered as "Turritella cf. robertiana"
Architaenioglossa - Ampullinidae	Ampullina stantoni Ampullina stantoni Murphy and Rodda 1960 snail quest. ident. - originally entered as "Ampulina stantoni"
Sorbeoconcha - Aporrhaidae	"Arrhoges californicus" = Latiala californica "Arrhoges californicus" = Latiala californica Gabb 1864 snail quest. ident.

¹Keupp 2008; ²Squires and Saul 2005