Oscillations of the Colifornia Coast. — Fairbaii/is. 217 
resemble rather that of the present Alaskan shore." The dif- 
ficalty of drawing a line of division between the Pliocene and 
Pleistocene is then discussed and the conclusion reached tiiat 
it can never be done on paleontological grounds, saying: "The 
reason for this is that there has been no distinct break in the 
continuity of marine conditions throughout the epochs, only 
a gradual transition of conditions. In this gradual transition 
there was however a reversal of tiie epeirogenic movement of 
the coast from a process of depression to a process of uplift. 
This turning point of the diastrophic pendulum, the intiation 
of the diastone of the epeirogenic pulsation is believed to cor- 
respond well with the beginning of the Pleistocene. The 
two epochs thus delimited have no interval of erosion between 
tliem and there will be found no marked break, except locally, 
in the sequence of marine life." 
In another paper professor Lawson* distinguishes Pleisto- 
cene terraces to a bight of IGOO feet and possibly more, with 
the remnants of a Pliocene ten-ace formed during the deposi- 
tion of the Wild-cat series. He recognizes three movements: 
(1) a depression during the Pliocene: (2) an orogenic move- 
ment at its close tilting the Wild-cat series; and (3) the gen- 
eral epeirogenic movement of the coast forming the terraces 
now so distinct. Speaking of the disturbances at the close of 
the Pliocene affecting portions of the coast he says: "These 
mountain-making movements were n(jt however adequate to 
efface the peneplain (Pliocene), and the general altitude of 
the coast was not apparently affected." We have then at this 
time according to professor Lawson, the curious anomaly of 
of mountain-making movements not affecting the level of the 
coast. 
The same investigator^ has described a complex series of 
events which he supposes took place upon the peninsula of San 
Francisco during the Pleistocene. The region is believed to 
have sunken through the Pliocene permitting the deposition 
of the Merced series which is about one mile thick. "At the 
close of these orogenic movements (deformation of the Mer- 
ced series) the altitude of the land was much lower relatively 
to the sea-level than at present. A general depression of the 
*Bull. of the Dpt. of Geo!., Univ. of Cal., Vol. I, p. 270. 
tXVth Annual report of the U. S. Geol. Sur., p. 468. 
