Monola Formation
Formation
Age[1]
PeriodCambrian
PrilithologyShale
OtherlithologyClay, Mudstone, Limestone, Siltstone
RegionCalifornia
CountryUnited States
OverliesMule Spring Limestone

The Monola Formation is a geologic formation in California. It preserves fossils dating back to the Cambrian period.

Geology

The Monola Formation is primarily composed of siliceous shales, and greyish-black clay shale, and calcareous siltstone. In parts of the siliceous shale, there are occasional layers of lime mudstone and bioclastic limestone.[2]

Paleobiota

The Monola Limestone contains a small collection of trilobites, like Glosopleura and Alokistocare.[3]

Arthropoda

GenusSpeciesNotesImages
Alokistocare[3]
  • Alokistocare sp.
Ptychoparid trilobite.
Syspacephalus[3]
  • Syspacephalus sp.
Ptychoparid trilobite.
Paraantagmus[2]
  • P. latus
Ptychoparid trilobite.
Amecephalus[2]
  • A. arrojosensis
Ptychoparid trilobite.
Mexicella[2]
  • M. robusta
Ptychoparid trilobite.
Onchocephalites[2]
  • O. laevis
  • O. resseri
Ptychoparid trilobite.
Syspacephalus[2]
  • S. variosus
  • S. granulosus (?)
Ptychoparid trilobite.
Tonopahella[2]
  • T. goldfieldensis
  • T. walcotii (?)
Ptychoparid trilobite.
Nyella (?)[2]
  • N. (?) plana
Ptychoparid trilobite.
Glossopleura[3]
  • Glossopleura sp.
Corynexochid trilobite.
Oryctocephalus[3][2]
  • Oryctocephalus sp.
  • O. orientalis
  • O. indicus
  • O. nyensis
Corynexochid trilobite.
Microryctocara[2]
  • M. nevadensis
Corynexochid trilobite.
Bathyuriscus[2]
  • Bathyuriscus sp.
Corynexochid trilobite, previously reported as Wenkchemnia sulcata and W. spinicollis.
Ogygopsis[3]
  • Ogygopsis sp.
Dorypygid trilobite.

See also

References

  1. ^ Stewart, J. H. "Upper Precambrian and Lower Cambrian Strata, in the Southern Great Basin California and Nevada". U.S. Geological Survery. Geological Survey Professional.
  2. ^ Sundberg, Frederick A. & McCollum, Linda B. (September 2003). "Early and Mid Cambrian trilobites from the outer‐shelf deposits of Nevada and California, USA". Palaeontology. 46 (5): 945–986. doi:10.1111/1475-4983.00328
  3. ^ Alpert, Stephen P. (1976). "Trilobite and Star-like Trace Fossils from the White-Inyo Mountains, California". Journal of Paleontology. 50 (2): 226–239. ISSN 0022-3360