The Campito Formation is a geologic formation in the Last Chance Range, California, and Esmeralda County, Nevada. It preserves fossils dating back to the Cambrian period.
Geology The Campito Formation is mainly composed of very fine to fine-grained quartzite, with small amounts of siltstone, getting up to thick. It is overlain by the Poleta Formation, whilst it is underlain by the Deep Spring Formation.
Members The formation is split into two distinct members, which are as follows, in ascending stratigraphic order (lowest to highest):
Andrews Mountain Member: It is the thickest of the two members, getting up to thick. It is composed of olive-gray or greenish-gray very fine to fine grained silty quartzitic sandstone or quartzite and interbedded layers of dark-greenish-gray siltstones, which weather to a greenish-black or just black. The quartzite layers are composed of sub-angular very fine to fine grains of quartz, feldspar and other metallic minerals, all set within a muscovite, chlorite, and biotite.
Montenegro Member: It is the thinnest of the two members, only getting up to thick. It is composed of dark-greenish-gray and greenish-gray siltstone composed of a mixture of quartz, muscovite, and chlorite. The siltstone is evenly laminated to thin-bedded. There are also commonly occurring archeocyathid-bearing limestone beds in the upper sections of the member.
Paleobiota The Campito Formation contains a number of fossils, most of which are found within the Montenegro Member. They range from archeocyathid sponges like Ethmophyllum, to arthropod trilobites like Nevadia, and a wealth of ichnogenera, from burrows like Skolithos, to resting traces like Rusophycus.
Arthropoda
GenusSpeciesNotesImagesFritzaspis Fritzaspis sp. F. generalis F. ovalisFallotaspidoid trilobite.Amplifallotaspis A. keniFallotaspidoid trilobite.Profallotaspis (?) Profallotaspis (?) sp.Fallotaspidoid trilobite.Archaeaspis A. nelsoni A. macropleuronFallotaspidoid trilobite.Cirquella C. nelsoniFallotaspidoid trilobite.Cambroinyoella C. wallaceiFallotaspidoid trilobite.Fallotaspis Fallotaspis sp. F. longaFallotaspidoid trilobite.Daguinaspis Daguinaspis sp.Fallotaspidoid trilobite.Repinaella Repinaella sp.Fallotaspidoid trilobite.Eofallotaspis Eofallotaspis sp.Fallotaspidoid trilobite.Nevadia Nevadia sp.Nevadiid trilobite.Judomia (?) Judomia (?) sp.Nevadiid trilobite, assignment to genus is very tentative.Montezumaspis M. parallela M. cometesHolmiid trilobite.Esmeraldina E. rowei E. elliptica E. cometes (?)Holmiid trilobite. E. cometes was previously identified as Fallotaspis tazemmourtensis.Holmiella Holmiella sp. H. millerensisHolmiid trilobite.Palmettaspis P. consorta P. lidensisHolmiid trilobite.Grandinasus G. auricampus G. patulusHolmiid trilobite.
Lobopodia
GenusSpeciesNotesImagesMicrodictyon Microdictyon sp.Xenusid lopopod.
Lophotrochozoa
GenusSpeciesNotesImagesMicrocornus Microcornus sp.Lophotrochozoan hyolith.Ladatheca Ladatheca sp.Lophotrochozoan hyolith.Parkula Parkula sp.Lophotrochozoan hyolith.Hyolithellus (?) Hyolithellus (?) sp.Lophotrochozoan hyolith.Obolella O. excelsisObelellid brachiopod.Pelagiella P. subangulataPelagiellid mollusc.Nisusia (?) Nisusia (?)sp.Kutorginid brachiopod.Sabellidites (?) Sabellidites (?) sp.Tubular fossil.Brachiopod indet. ???Indeterminate brachiopod, most likely an internal mold, possibly a poorly preserved Nisusia (?)sp. specimen, or another kutorginid brachiopod.Obelellid molds ???Molds of obelellid brachiopods.
Chancelloriidae
GenusSpeciesNotesImagesAllonia Allonia sp.Chancelloriid organism.Chancelloria Chancelloria sp.Chancelloriid organism.
Cnidaria
GenusSpeciesNotesImagesPaiutitubulites P. variabilisAnthozoan cnidarian.
Porifera (Sponges)
GenusSpeciesNotesImagesEthmophyllum (?) Ethmophyllum (?) sp.Archeocyathid sponge.
Echniodermata
GenusSpeciesNotesImagesHelicoplacus Helicoplacus sp.Oblong echinoderm.Isolated plates Eocrinoidea (?)Isolated plates, possibly of eocrinoid origin.
Foraminifera
GenusSpeciesNotesImagesPlatysolenitesP. antiquissimusAgglutinated hyperamminid foraminiferan.
incertae sedis
GenusSpeciesNotesImagesOnuphionella O. durhamiTubular fossil.Volborthella V. titaniusTubular fossil, originally described as Campitius.
Ichnogenera
GenusSpeciesNotesImagesCruzianaCruziana sp.Trails.PlanolitesPlanolites sp.Burrows.HelminthopsisHelminthopsis sp.Feeding trails.BelorhapheBelorhaphe sp.Burrows.CochlichnusCochlichnus sp.Burrows.ScoliciaScolicia sp.Burrows.RusophycusR. didymus R. radwanskiiResting trace of trilobites.BergaueriaBergaueria sp.Resting trace of cnidarians.ZoophycusZoophycus sp.Polychaete feeding traces.ArthrophycusArthrophycus sp.Polychaete trace.TeichichnusTeichichnus sp.Feeding trace.TreptichnusTreptichnus sp.Burrow, originally described as Phycodes.DiplichnitesDiplichnites sp.Arthropod trackways.SkolithosSkolithos sp.Burrows.
See also
List of fossiliferous stratigraphic units in Nevada Paleontology in Nevada
References