USGS visual identity mark and link to main Web site

Core OL-92 from Owens Lake, southeast California

Identification of mollusca from core OL-92-2, Owens Lake, California

James R. Firby
Mackay School of Mines, University of Nevada, Reno, Nevada 89557

Introduction

Thirty two samples from core OL-92-2, Owens Lake, California, were examined for fossil mollusks. Six taxa of mollusca were recorded, consisting of four gastropods and two pelecypods; these are listed in table 1, below. Amnicola sp. cf. A. limosa and Amnicola sp. are probably the same, and are included here as representing a single taxon, i.e. the genus. In addition, numerous Ostracoda were noted in several of the samples, but are not included in this analysis. The listing of the samples in table 2 follows depth, which is generally the same order as the list of samples provided by the USGS. In most instances, the shells were fragmented and rarely complete, identification was made by examination of several fragments of similar individuals under binocular microscope at 10X to 40X magnification. All samples were conserved as shipped, with a minimal amount of destructive analysis, in order to preserve them for future studies. Table 2 below gives the listing of taxa from each sample, and is organized by sample number, slug, drive, and depth.

Tables

  1. Faunal list
    Gastropoda
    Amnicola sp. cf. A. limosa
    ?Amnicola sp.
    Helisoma (Carinifex) newberryi (Lea)
    Hydrobia sp.
    Valvata sp. cf. V. sincera Say
    Pelecypoda
    Pisidium sp. cf. P. compressum Prime
    Anodonta sp. indet.
  2. Listing of fauna by sample 
    Sample	Drive	Slug	Depth	Description
801	16	A	100.90	Small shell of Helisoma (Carinifex) newberryi; unidentifiable shell fragments; partial interanl casts.
802	56	B	186.71	External mold of Helisoma (Carinifex) sp.; abundant Pisidium sp. cf. P. compressum; abundant miscellaneous unidentifiable shell fragments; abundant ostracoda.  Several of the Pisidium speciments with both valves, indicating in situ preservation with no post-mortem transport.
803	59	B	195.14	Helisoma (Carinifex) newberryi; miscellaneous unidentifiable shell fragmets.
804	59	B	195.70-195.72	Shell fragments of Pisidium; unidentifiable shell fragments.
810	62	A	206.60-206.78	Nacreous shell fragments, probably of Anodonta.
811	63	A	207.49-207.53	Miscellaneous shell fragments, undetermined; some nacreous fragments probably referable to Anodonta sp.
813	63	A	207.91-207.96	Abundant small fragments of nacreous shell, probably Anodonta.
814	63	A	208.29	Pisidium sp. undetermined.
815	62	A	208.39	Single fragment of ?Anodonta sp.
816 A	64	B	210.13	A: Anodonta sp.
816 B	64	B	210.13	B: Anodonta sp.
817	64	B	210.15	Pisidium sp. cf. P. compressum; nacreous shell fragments of Anodonta sp.; single broken shell of Helisoma (Carinifex) sp.
819	66	B	213.54	?Helisoma (Carinifex) sp undet.; miscellaneous shell fragments; ostracoda.
820	66	B	214.05	Abundant Pisidium compressum; ? Amnicola sp.; ostracoda.
821	67	A	216.93-217.01	Helisoma (Carinifex) newberryi; Pisidium sp. undet., unidentified shell fragments.
823	71	A	225.73-225.96	Unidentified gastroped shell fragments, exhibiting distortion from pressure.  One specimen of first 1 1/2 volutions of ?Helisoma. sp.
824	71	B	226.41-226.48	Valvata sp. cf. V. sincera; ?Amnicola sp. Remnants of color banding noted on Valvata.  Shell fragments of large (>1 cm) gastroped not identifiable.
828 A	100	A	284.24	A: Nacreous shell fragments of ?Anodonta; small, undetermined gastroped; ostracoda.
828 B	100	A	284.24	B: Nacreous shell fragments of ?Anodonta; miscellaneous unidentifiable gastroped shell fragments; ostracoda.
828 C	100	A	284.24	C: Hydrobia sp.
828 D	100	A	284.24	D: Large nacreous shell fragments of Anodonta sp.; Hydrobia sp.; ostracoda.
828 E	100	A	284.24	E: Hydrobia sp.
829	100	B	284.64	Unidentifiable gastroped shell fragments.
850	106	C	309.49	Nacreous shell fragments of Anodonta sp.
851 A	107	A	310.25	A: Nacreous shell fragments of ?Anodonta; unidentifiable fragments of gastroped.
851 B	107	A	310.25	B: Shell fragments of a sphaeriid pelecypod assignable to ?Pisidium sp.; nacreous fragments of ?Anodonta; miscellaneous unidentified gastroped shell fragments.
852 A	107	A	310.40	A: Pisidium sp. undet.; Hydrobia sp.; nacreous shell fragments of ?Anodonta sp.
852 B	107	A	310.40	B: Hydrobia sp.; nacreous shell fragments of ?Anodonta.
855	107	B	312.92	Nacreous shell fragments, ?Anodonta sp.; Amnicola sp. cf. A. limosa; unidentified fragments of larger gastropod.
855	107	B	313.97	Fragments of Pisidium sp. undet.
856 A	108	A	314.75	A: Nacreous shell fragments of ?Anodonta; Hydrobia sp., commonly present.
856 B	108	A	314.75	B: Hydrobia sp.; abundant nacreous shell fragments of ?Anodonta; ostracoda.
856	108	B	318.36	Hydrobia sp. undet.

    U.S. Department of Interior, U.S. Geological Survey
    URL of this page: https://pubs.usgs.gov/openfile/of93-683/6-organic/3-mollusc.html
    Maintained by: Eastern Publications Group Web Team
    Last modified: 03.01.01 (krw)