The Mission Valley Formation is a marine sandstone geologic formation in the Mission Valley region of southwestern San Diego County, California.Geiconsultants.com: Geologic Formations of Western San Diego County, by Jeffrey D. Brown, R.G., C.E.G. − circa 1996.
Geology The formation's sandstone characteristics are: soft and friable, light olive gray, fine to medium grained, and composed mostly of quartz and potassium feldspar. The Mission Valley Formation thins from the west to the east, with a maximum thickness of .
It overlies the Stadium Conglomerate formation and underlies the Pomerado Conglomerate formation.
Fossil content It preserves fossils dating back to the Paleogene period of the Cenozoic Era. The formation's rocks can contain a molluscan fauna in the western and central exposures and a land-mammal fauna in the eastern exposures.
Mammals Eulipotyphlans Eulipotyphlans reported from the Mission Valley Formation Genus Species Presence Material Notes Images ProterixoidesP. davisi Several calcaneums, astragali and a navicular.
Ferae Ferae reported from the Mission Valley Formation Genus Species Presence Material Notes Images CeruttiaC. sandiegoensis "SDSNH locality 4888, State Road 125 North (Unit II, Mid Brown Siltstone)".SDSNH 92504 and SDSNH 92503. A carnivoraform. cf. 'Miacis''' |cf. 'M.' hookwayi|SDSNH locality 4715, State Route 125 Grossmont. |SDSNH 84969 "right dentary fragment with p2, m1, and m2". |A miacid.
|Procynodictis|P. progressus''SDSNH locality 3870, Scripps Ranch North Site 70."SDSNH 54413 (left dentary fragment with p2-m2); SDSNH 54414 (right dentary fragment with m1-2); SDSNH 54416 (left maxillary fragment with P4-M1)".A miacid.
Primatomorphs Primatomorphs reported from the Mission Valley Formation Genus Species Presence Material Notes ImagesHemiacodonH. sp.V-72157.Isolated fragmentary teeth.An omomyid, most similar to H. gracilis.?Macrotarsius?M. sp.V-72150 & V-73138.Isolated molars.An omomyid also known from the Friars Formation, closely similar to M. jepseni.MicrosyopsM. sp. cf. M. annectensV-72158.Isolated & fragmentary molar (UCMP 101619).A microsyopid.NotharctusN. sp.V-72157.Damaged isolated molar (UCMP 113256).A notharctine similar to N. robustior.OmomysO. powayensisV-71180, V-72157 & V-72158.Teeth.An omomyid also known from the Friars Formation. PelycodusP. sp. V-73138.Maxillary fragment (UCMP 113210). A notharctine.UintasorexU. montezumicusV-71180, V-71211, V-72157, V-72158, V-72176, V-72177, V-72179, V-73138 & V-73139.Isolated teeth.A microsyopid also known from the Friars Formation.WalshinaW. esmaraldensisSDSNH localities 3426 and 4020.Teeth.An omomyid also known from the Sespe & Santiago formations.WashakiusW. woodringiV-71211, V-72157, V-72158, V-72176, V-72179 & V-73138.Teeth & jaw elements.An omomyid also known from the Friars Formation.
See also
List of fossiliferous stratigraphic units in California Paleontology in California
References
Further reading