164 BRUCE CLARK 
ornamented species common to the two, and also because of their 
generic assemblage. . 
Dickerson’s' conclusion was the same as that of Harris. He 
listed a much larger number of identical or nearly identical species 
common to the Claiborne and the Tejon. 
The nonconformity of the Meganos beds below the Tejon, 
together with the fact that the faunas of the two groups are very 
different, would seem to show that the former belong to a horizon 
lower than that of the lower Claiborne. That it does not repre- 
sent the lowest Eocene is shown by the fact that the beds of the 
Martinez Group, which contains a fauna very distinct from that of 
the Meganos, lie stratigraphically and unconformably below those 
of the Meganos. 
Dickerson’s? conclusion after studying the fauna of the 
Martinez was that it is “in part the correlative of the Midway of 
the Gulf States and in part represents a division of time earlier 
than the Midway.”’ : 
From our present knowledge of the Meganos fauna, its relation- 
ship appears to be closer to that of the Tejon than to that of the 
Martinez. If this be true, it would seem improbable that the 
Meganos is the equivalent of any part of the typical Midway 
stage. It more probably corresponds to the Wilcox. There is 
some direct evidence which appears to favor this assumption. 
This is the presence of species in the Meganos identical or nearly 
identical with certain well-known Middle Eocene species. For 
example Turritella merriamt Dickerson with its numerous varia- 
tions appears to be specifically close to Turritella humerosa Conrad, 
which is common in the Middle Eocene Wilcox of the Gulf province. 
One of the new species of turritella associated with Twurritella 
merriami in the Mount Diablo region appears to be identical in 
at least one of its variations with the species listed by Harris’ as 
T. humerosa var. 
= R. E. Dickerson, “‘Stratigraphy and Fauna of the Tejon Eocene of California,” 
Univ. Cal. Pub. Bull. Dept. Geol., Vol. TX (1919), No. 17, p. 476. 
2R. E. Dickerson, ‘‘Fauna of the Martinez Eocene of California,” Univ. Cal. 
Pub. Dept. Geol., Vol. VIII (1914), No. 6, p. 120-21. 
3G. D. Harris, ““The Midway Stage,’ Bull. Amer. Paleontology, No. 1, Pl. 11, 
Fig. 12 (1896). 
