Rhodes Canyon (1st endoceroid zone) (Ordovician of the United States)

Also known as San Andres Range, San Andres Mountains

Where: Sierra County, New Mexico (33.2° N, 106.7° W: paleocoordinates 13.0° S, 89.8° W)

• coordinate estimated from map

• small collection-level geographic resolution

When: Cooks Formation (El Paso Group), Demingian (485.4 - 478.6 Ma)

• "first endoceroid zone of the El Paso limestone" (Flower, 1964 p. 103); "The first endoceroid zone is distinguished as the Cooks formation [...] " (ibid. p. 148) actually refers to the rocks exposed in the Cook(e)s Range in Luna Co., NM; In fig. 50 the 1st endoceroid zone of the Cook(e)s Range section corresponds to interval A of Cloud & Barnes (1946, Univ. Texas Publ. 4621) and to the lower part of the Gorman Fm. (= Hag Hills Fm. in Goldhammer et al., 1993, J. Sed. Petr. 63(3)) of the southern Franklin Mts., El Paso Co., TX., and is referred to the middle Canadian.

• member-level stratigraphic resolution

Environment/lithology: perireef or subreef; shelly/skeletal grainstone

• Generally, the material collected from the 1st endoceroid zone is "largely from calcarenites in interstices in algal reefs" (p. 146)

Size class: macrofossils

Preservation: cast

Collection methods: NMBM = collections of New Mexico Bureau of Mines and Mineral Resources

Primary reference: R. H. Flower. 1964. The Nautiloid Order Ellesmeroceratida (Cephalopoda). State Bureau of Mines and Mineral Resources New Mexico Institute of Mining and Technology, Memoir 12:234 p. [B. Kröger/T. Liebrecht/P. Wagner]more details

Purpose of describing collection: taxonomic analysis

PaleoDB collection 88833: authorized by Björn Kröger, entered by Torsten Liebrecht on 22.04.2009

Creative Commons license: CC BY (attribution)

Taxonomic list

• "Here also occur[s...] a host of gastropods largely known from internal molds which permit only approximate determination, but including apparent Ozarkina, Ophileta, and Lytospira [...] " (p. 146). None of the gastropod genera is explicitly said to occur at Rhodes Canyon.
Cephalopoda
 Ellesmerocerida - Rioceratidae
Rioceras expansum n. sp. Flower 1964
NMBM 884 (type)
? Rioceras depressum n. sp. Flower 1964
NMBM 882 (holotype), 883 (paratype)