UCMP loc. 3151, north of Mount Diablo (Eocene of the United States)

Where: Contra Costa County, California (37.9° N, 121.8° W: paleocoordinates 40.6° N, 104.6° W)

• coordinate estimated from map

• outcrop-level geographic resolution

When: Meganos Formation, Ypresian (56.0 - 47.8 Ma)

• "Meganos" faunas represent upper Bulitian and lower Penutian local ages=Ypresian

• bed-level stratigraphic resolution

Environment/lithology: coastal; lithified, fine-grained, pebbly, calcareous sandstone

• Shallow marine coastal siliciclastic environment
• Fine, micaceous sandstone, commonly with small pebbles, thinly beeded near bottom, more massive at top, yellow-brown to gray in color. The massive sandstones near top contain lenses of harded calcareous and fossiliferous sandstones.

Size class: macrofossils

Reposited in the UCMP

Collection methods: quarrying,

• Collected by Clark and Woodford. Collections reposited at UCMP.

Primary reference: B. L. Clark and A. O. Woodford. 1927. The geology and paleontology of the type section of the Meganos Formation (lower Middle Eocene) of California. University of California Publications in Geological Sciences 17(2):63-142 [A. Miller/A. Hendy/P. Wagner]more details

Purpose of describing collection: biostratigraphic analysis

PaleoDB collection 52421: authorized by Austin Hendy, entered by Austin Hendy on 05.08.2005, edited by Mark Uhen

Creative Commons license: CC BY (attribution)

Taxonomic list

• Identified by Clark and Stewart.
Gastropoda
 Cerithioidea - Turritellidae
Turritella meganosensis n. sp. Clark and Woodford 1927 turret shell
Turritella merriami Dickerson 1913 turret shell
 Sorbeoconcha - Ficidae
Ficopsis meganosensis n. sp. Clark and Woodford 1927 fig shell
 Sorbeoconcha - Naticidae
Polinices (Euspira) nuciformis Gabb 1864 moon snail
 Opisthobranchia - Cylichnidae
"Scaphander cf. costatus" = Scaphander (Mirascapha) costatus
"Scaphander cf. costatus" = Scaphander (Mirascapha) costatus Gabb 1864 snail
Bivalvia
 Arcida - Glycymerididae
"Glycymeris major" = Glycymerita major
"Glycymeris major" = Glycymerita major Stanton 1896 clam
Subspecies: Glycymeris major meganosensis
 Mytilida - Mytilidae
"Modiolus (Brachydontes) ornatus" = Brachidontes (Brachidontes) cowlitzensis
"Modiolus (Brachydontes) ornatus" = Brachidontes (Brachidontes) cowlitzensis Weaver and Palmer 1922 mussel
 Lucinida - Lucinidae
"Phacoides meganosensis n. sp." = Miltha (Miltha) meganosensis
"Phacoides meganosensis n. sp." = Miltha (Miltha) meganosensis Clark and Woodford 1927 clam
 Cardiida - Veneridae
"Macrocallista meganosensis n. sp." = Microcallista (Costacallista) conradiana meganosensis Clark and Woodford 1927 venus clam
Pitar uvasana Conrad 1855 venus clam
Subspecies: Pitaria uvasana marshallensis
 Cardiida - Mactridae
"Spisula tejonensis" = Mactromeris tejonensis, "Spisula meganosensis n. sp." = Pseudocardium meganosensis
"Spisula tejonensis" = Mactromeris tejonensis Packard 1916 clam
"Spisula meganosensis n. sp." = Pseudocardium meganosensis Clark and Woodford 1927 clam
 Cardiida - Psammobiidae
Gari (Gobraeus) sp.2 Brown 1844 clam
Echinoidea
 Cidaroida - Cidaridae
"Hesperocidaris merriami" = Cidaris merriami1
"Hesperocidaris merriami" = Cidaris merriami1 Arnold 1908 pencil urchin
 Spatangoida - Schizasteridae
Schizaster cordiformis1 Kew 1920 heart urchin