Stratigraphic Nomenclature of the Central Santa Monica Mountains, Los Angeles County, California Page: E16
This report is part of the collection entitled: Technical Report Archive and Image Library and was provided to UNT Digital Library by the UNT Libraries Government Documents Department.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
CONTRIBUTIONS TO STRATIGRAPHY
Sandstone interbeds, chiefly medium- and fine-grained wackes (prob-
ably turbidites), are rare in the Point Dume quadrangle; they be-
come increasingly abundant westward in the Triunfo Pass quad-
rangle.
For the most part, the Encinal rests conformably on sandstone of
the underlying San Nicholas Member of the Vaqueros Formation, but
there is apparent discordance in some places where exposures do not
permit discrimination between local unconformity and possible fault
contact. The Encinal Member is unconformably overlain by the Con-
ejo Volcanics, generally with slight discordance. There may have been
no subaerial erosion separating Encinal deposition (marine sedimen-
tation) from Conejo deposition (volcanic flows and breccias that pro-
bably are chiefly submarine).
Poorly preserved Foraminifera in two collections from the type lo-
cality on Encinal Canyon Road are assigned to the Relizian (?) Stage
and Saucesian or Relizian Stages of Kleinpell (1938). This assignment
accords with that of Sonneman (1956), who reports that equivalent
strata farther west contained Foraminifera assignable to the Relizian
Stage.
SADDLE PEAK MEMBER
The Saddle Peak Member is here named for good exposures on the
west shoulder of Saddle Peak in the eastern Malibu Beach quad-
rangle. Its type locality is designated the roadcuts along Piuma Road
(NE/4 sec. 21, T.1 S., R.17 W) southwest of the peak (pl. 3D), where
about 220 m of thick-bedded to massive medium- to coarse-grained
sandstone, pebbly sandstone, and hackly sandy siltstone is present
above a 0.5-m-thick basal pebble conglomerate. The member is pres-
ent chiefly in the east part of the quadrangle, where it conformably
overlies the Piuma Member of the Sespe Formation and conformably
underlies the Fernwood Member of the Topanga Canyon Formation.
A resistant sandstone sequence near the base contains an abundant
"Temblor" megainvertebrate fauna that includes the gastropod Antil-
lophos dumbleanus (Anderson), apparently restricted to the middle
Miocene. Immediately above the basal conglomerate at this
locality-and commonly near the base of the Topanga Canyon Forma-
tion elsewhere-is a 10-cm-thick bed of well-cemented sandstone that
contains numerous well-preserved, in part articulated, valves of the
giant pectinid Vertipecten nevadanus (Conrad) (also called V bowersi
[Arnold]. The fauna is assigned to the "Temblor" Stage, middle
Miocene.
FERNWOOD MEMBER
The Fernwood Member is here named for exposures in the
Fernwood area of the west-central Topanga quadrangle where an in-E16
Upcoming Pages
Here’s what’s next.
Search Inside
This report can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Report.
Yerkes, R. F. & Campbell, Russell H. Stratigraphic Nomenclature of the Central Santa Monica Mountains, Los Angeles County, California, report, June 16, 1979; Washington D.C. (https://digital.library.unt.edu/ark:/67531/metadc304330/m1/22/: accessed April 19, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.