Page 12 - maxson1928

-position -0f Qp.aternary terrace gravels with respect to the }tint Canyon

formation. The -terrace gravels are dark brown in color and a.re apparently

flood plain.deposits. As yet no vertebrate fossils have been found in

them.

A hypothetical reconstruction of conditions during the period of

accumulation of the Mint Canyon series is naturally fallible but certain

observations seem justified. The faunal assemblage although meagre is a

group adapted apparently to semi-arid conditions. Relationship of the

fauna to the Barstow fauna as suggested by the presence of Merychippus

intermontanus indicates a possibility of freer communication with the

Mohave Desert than exists today. Faulting and folding have been active

in the region in Recent times. This late Cenozoic deformation is largely

responsible for the high relief of the present topography. A number of

streams including San Francisquito Creek find their sources on the north

side of the topographic divide between the Mohave Desert and the Santa

Clara Valley. In Figure 1. these relationships are roughly shown by the

sketch map. The streams appear to be antecedent. Thus open avenues of

connection probably existed in the late Tertiary and possibly as early

as the Miocene. However, some regions of high relief must have partially

enclosed the area in order to supply the co~rser sediments.

Nature of the Paleontologic Material

The mode of deposition of the Mint Canyon beds was not favorable

to burial of skeletal parts in association. Teeth occurring at particular

localities were scattered and sometimes weathered before burial. ~"he

fossiliferous horizons are infrequent in occurrence in the series. Good

specimens are exceedingly rare; a series of horse teeth and the anterior

portion of a camel skull being among the better specimens discovered.