A Caltech Library Service

Geomorphology of a Portion of the Easternmost Ventura Basin


Shoemaker, Eugene Merle (1947) Geomorphology of a Portion of the Easternmost Ventura Basin. Senior thesis (Major), California Institute of Technology. doi:10.7907/WEN7-KY40.


The Humphreys Quadrangle is a portion of the easternmost Ventura Basin underlain by a thick series of Tertiary sedimentary rocks. On these rocks a great variety of geomorphic forms have been molded by the processes of running water typical of a semi-arid climate and by several types of mass movement. Among the different categories of mass movement present, a new type, the siltflow, was observed.

The geomorphic forms of special interest present in the quadrangle are rock cones, open canyonheads, asymmetric canyons, and stream terraces and straths. The author urges the adoption of the definition of strath as that part of an old dissected valley floor, including the floors of tributary valleys, which was not part of the floodplain of the main valley stream.

An old erosion surface, the Puckett Mesa Surface, is present in the Humphreys Quadrangle which is correlative with certain of the older stream terraces. By correlating the variation of gradient and of fill of the stream terraces with post –Wisconsin climatic fluctuations the age of the Puckett Mesa Surface is set at approximately 6000 B.C. This correlation sets the probable age of the older Rancho La Brea deposits at 6000 to 8000 B. C. and the probable age of the Carpenteria brea deposits at 1000 to 1 B. C.

Item Type:Thesis (Senior thesis (Major))
Subject Keywords:Geology
Degree Grantor:California Institute of Technology
Division:Geological and Planetary Sciences
Major Option:Geology
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Unknown, Unknown
Thesis Committee:
  • Unknown, Unknown
Defense Date:1947
Record Number:CaltechTHESIS:07072015-094601408
Persistent URL:
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:9049
Deposited On:08 Jul 2015 16:22
Last Modified:22 Mar 2023 18:29

Thesis Files

PDF - Final Version
See Usage Policy.

PDF (Longitudinal profile over former stream of Puckett Mesa) - Supplemental Material
See Usage Policy.


Repository Staff Only: item control page