STRATIGRAPHY OF SOUTHERN CALIFORNIA 135 
Pedro series, are probably unconformable with the lower fossilif 
erous strata (a fossiliferous fragment of the latter being found 
in the former) although the exact relation between the two 
horizons was not definitely determinable stratigraphically, owing 
to the prevalence of false bedding in the upper beds. Asphaltum 
impregnates the gravels and sands in several places where they 
rest upon the Miocene shales. An Indian kitchen midden over- 
lies the Pleistocene deposits one-eighth of a mile west of the 
bath house. 
RELATION BETWEEN THE SOUTHERN CALIFORNIA PLIOCENE AND 
PLEISTOCENE AND THE MERCED SERIES. 
A series of sandstones and shales over five thousand feet in 
thickness is exposedin the sea cliff which extends for a few 
miles south of Lake Merced on the San Francisco peninsula. 
This series of beds has been described by Dr. A. C. Lawson,’ 
who named it the Merced series. Dr. Lawson places the whole 
series, with the exception of about one hundred feet of strata 
Aue topy iteticlnocene7 s Dr G bi Ashileyicvictravws), tlre 
Pliocene-Pleistocene line further down in the series, or at the 
base of a fossiliferous stratum which has received the local name 
‘upper gastropod bed.” A study of the faunas of the different 
layers of the merced series has led the writers to draw the line 
in the same place that Dr. Ashley has drawn it. Although 
there is a distinct faunal break between the ‘‘ upper gastropod 
bed” and the subjacent layers, there seems to be no indication 
of any decided interruption in the sedimentation in this part of 
UNS SERMES; 
Dr. Dall3 places the San Diego formation, with which he 
correlates the Deadman Island Pliocene, below the Merced 
series. This does not agree with the conclusions arrived at by 
*A.C. Lawson, “ The Post-Pliocene Diastrophism of the Coast of Southern 
California,” Bull. Dept. Geol., Univ. of Cal., Vol. 1, pp. 142-50, 1892. 
2 GEORGE H. ASHLEY, ‘“‘ The Neocene of the Santa Cruz Mountains, Proc. Cad. 
Acad. Sci., 2d Series, Vol. V, pp. 312-37, 1895. 
3W. H. Dati, “Correlation Table of North American Tertiary Horizons,” 
Eighteenth Ann. Rep. U.S. Geol. Surv., Pt. Il, p. 335, 1898. 
