TRILOBITES OF THE ANTELOPE VALLEY LIMESTONE:

Antelope Valley Formation, Whiterockian Series, Psephosthenaspis Zone (of Fortey), Whiterock Canyon Narrows (after Fortey and Droser, 1999). See also the Ninemile Shale Formation.

Trilobites:

WHITEROCK CANYON

Acidophorus? lineotuberculatus (Fortey and Droser, 1999)

Ampyxina (or Ampyxoides?) n. sp.

Ampyxoides cf. occipitalis Dean, 1973

Apatolichas cf. jukesi (Billings, 1865)

Carolinites sibiricus Chugaeva, 1964 (=? angustagena)

Cybelopsis cf. C. speciosus

Ectenonotus whittingtoni Ross, 1967

Harpillaenus rossi Fortey and Droser, 1999

Illaenus cf. I. auriculatus Ross, 1967

Ischyrotoma stubblefieldi Ingham, 1986

Madaraspis magnifica Fortey and Droser, 1996

Nileus hesperaffinis Ross, 1967

Poronileus vallancei Fortey, 1975

Pseudomera arachnopyge

Raymondaspis vespertina Ross, 1967

LITTLE RAWHIDE MOUNTAIN:

Lower Whiterockian:

Bienvillia papulosa (Fortey, 1974)

Carolinites sibiricus Chugaeva, 1964 (=? angustagena)

Carolinites n. sp. (see Fortey and Droser, 1999)

Cloacaspis tesselata Fortey and Droser, 1999

Cybelurus halo Fortey, 1980

Ectenonotus whittingtoni Ross, 1967

Peraspis erugata Ross, 1967

Poronileus fistulosis Fortey, 1975

Protocalymene n. sp. A (see Fortey and Droser, 1999)

Shumardia exopthalmus Ross, 1967

Upper Ibexian:

Lachnostoma sp.

Ptyocephalus sp.

MEIKLEJOHN PEAK:

Lower Whiterockian:

Apatolichas sp.

Benthamaspis sera Fortey and Droser, 1999

Cybelurus halo Fortey, 1980

Harpillaenus rossi Fortey and Droser, 1999

Illaenus cf. I. auriculatus Ross, 1967

Ischyrotoma aff. stubblefieldi Ingham, 1986

Kawina wilsoni

Opipeuter sp. (see Fortey and Droser, 1999)

Protopresbynileus cf. glaber Fortey, 1975

Pseudomera sp. indet. (see Fortey and Droser, 1999)

Upper Ibexian:

Lachnostoma latucelsum Ross, 1951

Protopresbynileus utahensis

Ptyocephalus declivita

Also reported:

Pseudomera cf. barrandei (Billings)

Protocalymene mcallisteri ROSS, 1967 is also reported from the Antelope Valley Fm, California - although we're not sure which level.

COMMENTS:

The base of the Whiterockian (contact with Ibexian) is under some controversy and the trilobite faunas within the Antelope Valley Limestone and Ninemile Shale vary from place to place. At Whiterock Canyon, the "spike" at the base of the Whiterockian occurs at the boundary between the Ninemile and Antelope Valley Formations. At other localities (Rawhide, Meiklejohn Peak), the base of the Whiterockian doesn't necessarily coincide with formational boundaries. The trilobite faunas also vary due to different facies and correspondingly different trilobite biofacies. The trilobite faunas of Rawhide and Meiklejohn Peak are included here (split into Lower Whiterockian and Upper Ibexian). For more information, see Fortey and Droser ( 1999).

REFERENCES:

Fortey, R. A. and Droser, M. L. (1999)  Trilobites from the base of the type Whiterockian (Middle Ordovician) in Nevada. Journal of Paleontology, Vol. 73, No. 2, pp. 182-201

Loch, J. D. (2002)  Trilobite biostratigraphy across the base of the Whiterockian Series (Ordovician) for the proposed GSSP at Whiterock Canyon, Nevada. (web document)

Loch, J. D.  (2001)  New trilobite occurrences in the Whiterock Narrows section. (web document)