Earlier Work on the California Lower Tertiary Sequence
Published:January 01, 1959
Early workers in California considered the Eocene formations we recognize today to be within the upper limits of the Cretaceous System. Gabb (1864) referred beds containing Trochocyathus striatus (Gabb) and underlying coal-bearing strata to his Division “B” of the Cretaceous. In 1869 he revised his Division “B” and renamed it the Tejon Group but continued to regard this as a division within the Cretaceous. Timothy Stanton in 1895 and again in 1896 referred Gabb’s Tejon Group to the Eocene. Stanton also made a further subdivision within Gabb’s Tejon into a lower and an upper, or Tejon, horizon. The name “Martinez” was subsequently given to the strata of the lower horizon by Whitney in the preface to Gabb’s descriptions of Cretaceous and Tertiary fossils (1869). Whitney defined the term “Martinez Group” as including the beds found in the vicinity of the town of Martinez and on the northern flank of Mount Diablo. Concerning the origin of the term “Tejon,” Anderson and Hanna (1925, p. 5) have this to say:
In 1854 a portion of the Pacific Railroad Survey expedition … camped in what is now Kern County, California, in the vicinity of old Fort Tejon. The geologist of the party, W. P. Blake, made numerous excursions in the region during which some paleontologic specimens were collected. In “Canada de las Uvas”… he picked up a float boulder containing fossils and this soon passed into the hands of T. A. Conrad. Several species new to science were detected in the small collection
Figures & Tables
Lower Tertiary Biostratigraphy of the California Coast Ranges
As a result of field work carried on in 1947 a sequence of foraminiferal samples were collected in 2,300 feet of Lower Tertiary mudstones, siltstones, and interbedded shales and sandstones in the vicinity of Media Agua Creek, in the Temblor Range on the west side of the San Joaquin Valley.
Foraminiferal samples from another less comprehensive sequence of Lower Tertiary strata were collected during the years 1947, 1948, and 1949 in the region of Devils Den.
The prepared samples were studied during the years 1947–1952 in the Department of Paleontology at the University of California under the direction of Dr. Robert M. Kleinpell. Subsequent work both in the field and laboratory has been directed toward obtaining as complete and chronologically diagnostic a faunal sequence throughout the Lower Tertiary in the California province as possible.
Preliminary results of certain phases of the investigation have been presented from time to time at meetings of the Pacific Section of the American Association of Petroleum Geologists, San Joaquin Valley Geological Society, Cordilleran Section of the Geological Society of America, and the Northwest Geological Society (Mallory and Boyd, 1949; Mallory, 1953a, 1953b, 1954a, 1954b). This paper attempts a synthesis and revision of these reports and their conclusions, and the incorporation of many new data.
The majority of species known to be important in the Paleogene foraminiferal faunas are figured and their stratigraphic distribution in the California province is noted. In addition, an attempt has been made to draw any inferences from all kinds of fossil