Illustration of an oreodont — in this case a merycoidodon, similar to those that populated the SCV for 30 million years (until ~4.9 MYA). Artwork by Heinrich Harder (1858-1935). Oreodonts were hog-like ruminants. This illustration and the map below are not part of Whistler's paper. Click to enlarge.
In 1940, Richard H. Jahns reviewed the stratigraphy of
the nonmarine Mint Canyon Formation in the eastern part of
the Ventura Basin and separated from it a new formation and
fauna. Previous to this work, a controversy existed as to
the age of the Mint Canyon Formation, for it contained
vertebrates considered indicative of both the Miocene and
Pliocene (Kew, 1924, Maxson, 1930, and Stirton, 1933). As a
partial solution to this controversy, Jahns demonstrated the
presence of an erosional unconformity low in the nonmarine
sequence which indicated a shift in source area. He
redefined the beds below the unconformity as the Tick Canyon
Formation (Jahns, 1940, pp. 163-66).
The composite Tick Canyon fauna as presently known is
as follows: a heteromyid rodent, Trogomys rupinimenthae
Reeder, 1960, a rabbit, Archaeolagus acaricolus Dawson,
1958, two oreodonts, Merychyus (Merychyus) calaminthus Jahns,
1940, and Merychyus (Merychyus) jahnsi (this paper), a camel,
Miolabis californicus Maxson, 1930, and a stenomyline camel
(previously unpublished record).
All California Institute of Technology collections are
now conserved in the Los Angeles County Museum of Natural
History. With the consent of this institution, the author
was able to study the entire sample of oreodonts from the
Tick Canyon fauna, which includes an additional maxillary
fragment collected by Miss Beth Chasse, an associate of the
Locality identified in Whistler's paper: Southwest corner of Section 25, Township 5 North, Range 15 West, S.B.M. Click map to enlarge.
Download pdf here
. Courtesy of Stan Walker.