4 



shells. The lower 700 to 800 feet, as exposed in Ellsrnere Canyon, 

 is a coanse shale made up chiefly of rather angular fragments and 

 some volcanic ash. ITone of the shale was found to be diatomaceous. 

 Towards the upper part the shale becomes coarser, and grades into 

 sandstone. These "beds, especially in the lower part, contain hard 

 round concretions from six inches to three feet in diameter. The 

 concretions are fossilif erous, containing shells, mammal bones, 

 fossil wood fragments, and teredo borings. These beds are all stain- 

 ed a chocolate color by petroleum, and in places the bitumen is 

 abundant enough to form a cementing material. Near Ellsmere Ridge 

 there are a number of brea deposits formed by oil seepages; and the 

 Ellsmere Canyon oil wells drew their supply from these lower strata. 



Stratigraphically above the fine sandstones and shales is a 

 series of cross bedded alternating coarse sandstones and conglomer- 

 ates. These strata are well exposed on the sides of Ellsmere Ridge, 

 in Whitney Canyon just north of Ellsmere, in Placerita Canyon, and 

 they extend for an unknown distance eastward along the northern 

 flank of the San Gabriel Range. In Ellsmere Canyon the conglomer- 

 ate consists of well rounded pebbles and boulders up to twelve inches 

 in diameter of granitic, and less commonly of volcanic rocks. The 

 pebbles are of all sizes, and grade down into the sand which fills 

 the interspaces. The induration is slight, most samples can be 

 broken between the fingers. The color is a light buff. 



The lower sandstone and shale beds were called Vaqueros by 

 Eldridge, and the two were considered to be structurally unconform- 

 able by him. The writer believes the entire series to be conform- 

 able. The relations of the two lithologic units are well shown on 



