Martiñez (Paleocene to of the United States)

Also known as Martinez; UCMP IP244

Where: Contra Costa County, California (38.0° N, 122.1° W: paleocoordinates 43.4° N, 100.8° W)

• coordinate based on nearby landmark

• outcrop-level geographic resolution

When: Vine Hill Formation, Selandian to Selandian (61.6 - 56.0 Ma)

• There are three, or perhaps four, formations outcropping in the vicinity of the town of Martinez from which Gabb might have obtained his specimen. According to Gabb, his illustrated specimen comes from the older member (Division A), associated with Turritella saffordi, Venus varians, Pugnellus hamulus... If Turritella saffordii (equals T. pachecoensis Stanton) actually occurred with the cephalopod, the age of Gabb's species would then be Martinez. However, Gabb's "Martinez Division A" included a mix of Cretaceous and Cenozoic collections, so was likely collected over a broad area, and might come from the Vine Hill Sandstone (Selandian-Thanetian), Las Juntas Shale (Ypresian), or Muir Sandstone (Ypresian-basal Lutetian). The lithological description (lacking glauconite and containing angular feldspars) might be more consistent with the Muir Sandstone, but the occurrence in "Division A" could suggest the Vine Hill Sandstone. That formation is tentatively assigned here. The lower Vine Hill Sandstone includes the Selandian Turritella peninsularis Zone of Soul (1983) and the middle Vine Hill includes the Selandian Turritella infragranulata pachecoensis Zone. Bukry et al. (1998) found calcareous nannofossil zones CP5, CP10, and CP11 in the upper Vine Hill Sandstone (latest Selandian-Ypresian), implying an age no younger than Selandian for the lower Vine Hill. McDougall (2007) assigned the Vine Hill to the Ynezian benthic foraminferal zone, correlated with planktonic zone P4 and nannofossil zones CP5-CP7, of Selandian-Thanetian age.

• group of beds-level stratigraphic resolution

Environment/lithology: coastal; lithified, calcareous sandstone

• Benthic foraminifera reported by McDougall (2007) reflect depths no shallower than middle-outer neritic, but also range in many cases to bathyal or even abyssal depths. However, the foraminifera may be from the finer-grained parts of the former "Martinez" and the sandy macrofossiliferous units are perhaps shallower.
• Very fine-grained calcareous sandstone with abundant quartz, angular feldspars, and calcite, some chlorite, and a fragment of a foraminifera, probably Robulus. No glauconite was noted.

Size class: macrofossils

Collected by E. Mathewson; W. P. Popenoe in 1944; reposited in the LACM, UCMP

Primary reference: W. M. Gabb. 1864. Description of the Cretaceous fossils. Geological Survey of California Palaeontology 1:57-217 [M. Clapham/M. Clapham]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 180454: authorized by Matthew Clapham, entered by Matthew Clapham on 17.07.2016

Creative Commons license: CC BY (attribution)

Taxonomic list

Show authors, comments, and common names
Cephalopoda
 Nautilida - Hercoglossidae
"Aturia mathewsonii n. sp." = Aturoidea mathewsonii
"Aturia mathewsonii n. sp." = Aturoidea mathewsonii Gabb 1864 nautiloid