130 BRUCE CLARK 
that sufficient evidence was obtained to show that the fauna of 
the Meganos belongs to the same epoch of deposition as the Eocene 
marine beds in the vicinity of Marysville Buttes and at Table 
Mountain near Oroville. ‘These beds generally have been referred 
to the Ione formation, and considered to represent the uppermost 
Eocene of the West Coast. Astatement to this effect was included 
in a note at the end of the paper and in the summary of conclusions. 
Briefly summarized, the most important results brought out 
in the paper last mentioned are: that in the Eocene of the region 
of Mount Diablo there are at least three groups instead of two, 
as was formerly believed; and that the beds of this newly recognized 
epoch of deposition come between those of the Martinez (Lower 
Eocene) and those of the Tejon (Upper Eocene). It was found 
that the Meganos Group on the north side of Mount Diablo has 
a maximum thickness of nearly three thousand feet. ‘These beds 
previous to this time had been generally mapped as Tejon. The 
unconformity between the Meganos and the Tejon in this area 
is such a marked one that it may be classed as one of the major 
breaks in the Tertiary of the Coast ranges. In places there is 
a difference of from 15° to 20° in strike, and a maximum difference 
of about 18° in dip between the beds of the Meganos and those 
of the Tejon above. It was also the conclusion of the writer that 
there is a marked difference between the fauna found in the beds 
below and that in the beds above this unconformity, and finally 
that the beds of the Meganos Group have a fairly wide distribution 
throughout the Coast ranges of California, in some localities having 
been mapped as of Martinez, and in others of Tejon, age. 
PURPOSE OF PAPER 
The purpose of this paper is to sum up the results of more 
recent studies of other Eocene sections in different parts of the 
Coast ranges, including the Mount Diablo section, which was 
described somewhat in detail in the first paper. The most impor- 
tant contribution is the evidence which shows that there are three 
general divisions in the Eocene of California, namely, the Martinez, 
Meganos, and Tejon, each of which may be considered as belonging 
to a distinct epoch. After discussing the various Eocene sections, 
reasons will be given for correlating the beds referred to the Meganos 
