{{Short description|Miocene epoch geologic formation in southern California, United States}} {{Infobox rockunit | name = Topanga Canyon Formation | image = | caption = | type = Formation | age = Neogene | period = Neogene | prilithology = | otherlithology = | namedfor = | namedby = | region = Santa Monica Mountains<br />Los Angeles County, California | country = United States | coordinates = | unitof = | subunits = | underlies =Modelo Formation | overlies = | thickness = | extent = | area = | map = | map_caption = }}

The '''Topanga Canyon Formation''' ({{IPAc-en|t|ə|ˈ|p|æ|ŋ|ɡ|ə|audio=En-us-Topanga.ogg}}) is a Miocene epoch geologic formation in the Santa Monica Mountains, Simi Hills, Santa Ana Mountains and San Joaquin Hills, in Los Angeles County, Ventura County, and Orange County, southern California.<ref name=usgssimi>[https://pubs.usgs.gov/of/1997/of97-259/ USGS.gov: "Preliminary Geologic Map of the Simi 7.5' Quadrangle, Southern California, A Digital Database"]; Open-File Report 97-259; compiled by R.F. Yerkes and R.H. Campbell; 1997.</ref> It is primarily composed of hard sandstone with some inter-bedded siltstone.

==Fossils==

It preserves fossils dating back to the Miocene epoch of the Neogene period, during the Cenozoic Era.<ref>{{cite web|title= Fossilworks: Gateway to the Paleobiology Database|author= ((Various Contributors to the Paleobiology Database))|url= https://www.fossilworks.org|access-date= 17 December 2021}}</ref><ref>{{Cite web|url=http://research.nhm.org/ip/topanga-formation/|title=Topanga Formation &#124; Invertebrate Paleontology @ NHM}}</ref>

==See also== {{Portal|California|Paleontology|Earth sciences}} * {{C|Miocene California}} * List of fossiliferous stratigraphic units in California * Paleontology in California * {{C|Santa Monica Mountains|Santa Monica Mountains-related topics}}

==References== {{Reflist}}

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Category:Miocene California Category:Geology of Los Angeles County, California Category:Geology of Ventura County, California Category:Miocene geology Category:Santa Monica Mountains Category:Simi Hills Category:Topanga, California Category:Geologic formations of California

{{California-geologic-formation-stub}} {{Neogene-stub}}