The Modelo Formation is a Miocene geologic formation in the Simi Hills and western Santa Susana Mountains of southern California, including under parts of Los Angeles.
It preserves fossils dating back to the Late Miocene of the Neogene period, among them a high number of fossil representatives of modern pelagic and deep-sea fish taxa (as well as some with benthic affinities), in addition to some seabirds and cetaceans. As suggested from this fauna, the sediments of the formation were likely deposited in a deepwater marine habitat at middle to upper bathyal depths within an abyssal fan, with geological changes along the San Andreas fault causing a rapid uplift during the latest Miocene, bringing these former deepwater sediments to the surface. It is likely partially contemporaneous with the Monterey Formation in some areas, such as the Ventura Basin.
Volcanic ash beds are known from the formation; these, along with fossil microorganisms, indicate that the formation was deposited between 13 and 5.5 million years ago.
Paleobiota Based on the Paleobiology Database and Fierstine et al (2012). Much of the fauna is shared with the Monterey Formation, though some distinct taxa are also known:
Bony fish Based on Fierstine et al (2012). Many of these taxa were described by David Starr Jordan from specimens excavated during the construction of the Sepulveda Boulevard Tunnel through the Santa Monica Mountains. GenusSpeciesLocationMemberMaterialNotesImagesAbsalomichthysA. veliferArticulated skeletonsA manefish.AraeosteusA. rothiArticulated skeletonsA relative of the prowfish.ArgyropelecusA. bullockiiArticulated skeletonsA marine hatchetfish.BathylagusB. angelensisArticulated skeletonsA deep-sea smelt.BolinichthysB. sp.Articulated skeletonsA lanternfish.ChalcidichthysC. malacopterygiusArticulated skeletonsA manefish.ChauliodusC. eximiusArticulated skeletonsA viperfish.?Clupea?C. tiejeiArticulated skeletonA herring, classification in Clupea uncertain.CyclothoneC. solitudinisLowerArticulated skeletonA bristlemouth.DecapterusD. hopkinsiArticulated skeletonA mackerel scad.D. sp.DiaphusD. boliniArticulated skeletonsA lanternfish.EclipesE. santamonicaeArticulated skeletonsA cod.E. veternusEtringusE. scintillansArticulated skeletons, isolated scalesA herring, possibly a round herring.GanolytesG. aratusArticulated skeletons, isolated scalesA herring.G. cameoHipposyngnathusH. imporcitorUpperArticulated skeletonsA pipefish.PlectritesP. classeniArticulated skeletonsA seabream.QuaesitaQ. quisquiliaArticulated skeletonsA deep-sea smelt.LampanyctusL. petroliferArticulated skeletonsA lanternfish, L. petrolifer potentially in an undescribed genus.L. sp.LaytoniaL. californicaArticulated skeletonA halosaur.LompoquiaL. culveriArticulated skeletonA drumfish.L. retropesL. sp.Molidae indet.An ocean sunfish.MyctophumM. sp.Articulated skeletonsA lanternfish.PseudoseriolaP. gilliandiArticulated skeletonsA relative of the bluefish.P. sp.RhomurusR. fulcratusPartial skeletonA halfbeak, either in the Hemiramphidae or the extinct Forficidae.SardaS. stockiiPartial skeletonsA bonito.ScomberS. sanctaemonicaePartial skeletonA true mackerel.S. cf. japonicus (=Pneumatophorus cf. grex)ScaleS. sp.Mulholland DrivePartial skeletonsScomberesoxS. edwardsiLowerSkull, partial segment with scalesA saury.ScorpaenaS. ensigerArticulated skeletonsA scorpionfish.SebastesS. davidiArticulated skeletonsA rockfish.S. sp.SyngnathusS. avusArticulated skeletonsA pipefish.ThyrsoclesT. kriegeriArticulated skeletonsA euzaphlegid.XyneX. grexArticulated skeletons, isolated scalesA herring.ZanteclitesZ. sp.Isolated scalesA Neotropical silverside.ZaphlegulusZ. venturaensisA euzaphlegid.
Birds Based on the Paleobiology Database: GenusSpeciesLocationMemberMaterialNotesImagesOsteodontornisO. orriSherman OaksA pseudotooth bird.PhalacrocoraxP. femoralisA cormorant.PuffinusP. diatomicusSherman OaksIncomplete skeleton.A shearwater.SulaS. willettiSherman OaksLeg bones.A booby.
Mammals Based on the Paleobiology Database: GenusSpeciesLocationMemberMaterialNotesImagesAtocetusA. nasalisUpperA kentriodontid toothed whale.MixocetusM. elysiusLincoln HeightsElysian Park SandstoneSkullA tranatocetid baleen whale, for which the formation is the type locality.
See also
List of fossiliferous stratigraphic units in California Paleontology in California
References