324 CALIFORNIA ACADEMY OF SCIENCES. 



ist. Petrographically the beds are similar to the Mer- 

 ced series. 



2d. Faunally there is a strong resemblance, many of 

 the species, if not a majority, being common to both. 



3d. They and the Monterey series differ petrograph- 

 ically, the White shale being a white, thin bedded, silicious 

 shale, while the upper formation is largely an argillaceous 

 sandstone, sometimes becoming an arenaceous clay, and 

 sometimes becoming very sandy. The latter is seldom 

 thin bedded, generally showing but few bedding planes 

 in a considerable thickness. The thin beds of conglom- 

 erate of the latter have not been noted in the White 

 Miocene shales. 



4th. They differ greatly in their faunas. The White 

 shale having a small fauna but sparsely represented, while 

 the Transition beds as well as the Merced series have an 

 abundant fauna, widely and abundantly represented. 

 Further, of the species quoted as found in the White 

 shale, only one species, the JLiicina borealis Linn., has 

 been noted among the Transition beds. 



5th. The position of strata at San Fernando and Los 

 Angeles, where beds whose fauna seem to place them in 

 the same horizon as the Merced series are to be seen over- 

 lying the White shale. Also the finding by Professor 

 Whitney of "A group of rocks, newer in age than the 

 bituminous shale,"* east of Monterey, whose fossils ally 

 them to the Transition beds of the Santa Cruz Mountains. 

 He quotes the following species from this locality : 



Neptunea recurva Gabb. 

 Modiola recta Conrad. 

 Modiola capax Conrad. 

 Area canalis Conrad. 



Structure. — Plate xxiv gives a section of the strata as 

 *Geol. Surv. of Cal., Geology, vol. i, p. 154. 



