Vol. VII] GESTER— GEOLOGY McKITTRICK DISTRICT 211 



tion indicates the former. Observations and de- 

 tailed mapping both to the north and to the south of 

 this area show quite clearl}^ that both of these for- 

 mations contain organic shales, and are separated by 

 local and probably by regional unconformities. 



There are well marked unconformities in the South-End 

 McKittrick area between the Tulare and Etchegoin. and be- 

 tween the latter and the underlying shale series. Identical 

 conditions are found in nearly every locality in the West Side 

 Fields where the overlapping Tulare has not completely 

 covered the Etchegoin. (lood examples of this unconform- 

 able condition are to be seen in the Gold Hills northwest of 

 McKittrick, and in the vicinity of Fellows and on Muddy 

 and Los Lobos creeks in the San Enu"gdio Ranch. Poorer 

 exposures are found southeast of Fellows and just south of 

 old Sunset. 



SUPERFICIAL DEPOSITS 



The only superficial deposits worthy of note are some of the 

 remnants of former stream flood-plains. In this particular 

 area, many of these contain oil sands or materials impregnated 

 with oil which in some places largely consist of impure as- 

 phaltum. The latter beds are usually spoken of as brea beds. 

 They are formed along the sides of the gulches below the oil 

 and tar springs. Where sandy they are distinctly cross- 

 bedded, but when composed largely of asph -Itum with minor 

 amounts of angular shale and sand fragments they show very 

 poor bedding. A few bones of extinct animals have been 

 found buried in these beds, among which are some classed by 

 Prof. J. C. Merriam as belonging to a species of dog, or 

 wolf. Some horse and elephant bones have also been reported 

 from this locality. These are of Quaternary age. In the 

 more recent deposits are occasional bones of small birds and 

 rodents, but they are far less numerous than in the Rancho 

 La Brea deposits of Los Angeles. On an old stream terrace 

 in the workings of the abandoned asphaltum mines, some 

 mammalian remains considerably older than those above re- 

 ferred to were found and are now in the possession of Prof. 

 J. C. Merriam at the University of California. 



