Pleistocene Terrace Deposits in Estero San Antonio

Two interpretations of 1 valley

by

Robert Davies

Location Map

Work completed by Hitchcock, C.S., Kelson, K.I., 1998,

Assessment of Seismogenic Sources between the Rodgers Creek and San Andreas Faults, Northwestern San Francisco Bay Region, Sonoma County, California

Helley, E. J., Lajoie, K. R., Spangle, W. E, Blair, M. L., 1979, Flatland deposits of the San Francisco Bay Region, California—their geology and engineering properties, and their importance to comprehensive planning

Hitchcock and Kelson

Qt3

Qt3

Qt2

Qt3

Qt4

Qt4

Helley et al.

Time scale

Comparison of datesHelley Hitchcock Fossils

Qt4 25-130 ka

Qt3 130ka-550 ka Camel, sloth, bison, mastadon

Qpea 70 ka- 1.8 ma Qt2 320 ka sloth

Qpa 35-70 ka

Fossil age Ranges

1 2 3 4 E M L I S W RecentPERISSODACTYLA

EquidaeNannippus beckensis

Nannihippus phlegonEquus simplicidens

Equus parastylidensEquus cumminsii

Equus calobatusEquus hemionus

Equus tauEquus giganteus group

Equus occidentalisEquus complicatus

Equus fraternusEquus scotti

Equus niobrarensisEquus conversidens

Equus lambeiEquus excelsus

Holocene

Irvingtonian RancholabreanBlancan

PleistocenePliocene

1 2 3 4 E M L I S WARTIODACTYLA

CamelidaeTitanotylopus nebraskensisTitanotylopus spatulusBlancocamelus meadeiMegatylopus cochraniCamelops kansanusCamelops traviswhiteiCamelops sulcatusCamelops huerfanensisCamelops minidokaeCamelops hesternusHemiauchenia blancoensisHemiauchenia macrocephalaPalaeolama mirifica

Blancan Irvingtonian Rancholabrean

1 2 3 4 E M L I S W RecentPROBOSCIDEA

MammutidaeMammut americanumElephantidaeMammuthus meridionalisMammuthus columbiMammuthus jeffersoniiMammuthus primigenius

Blancan Irvingtonian Rancholabrean

1 2 3 4 E M L I S W RecentEDENTATA

MegatheriidaeEremotherium rusconiiNothrotheriops shastensisMylodontidaeGlossotherium chapadmalenseGlossotherium harlini

Blancan Irvingtonian Rancholabrean

Problems in the maps

Formations mapped differently units have different ages based on

the same fossils!