FAUNAL RELATIONSHIPS OF THE MEGANOS GROUP 133 
Summary of lithology of sectton.—The outline below is a gen- 
eralized section of the Eocene groups as found on the north side of 
Mount Diablo. The Martinez portion of the section is copied 
from Dickerson’s paper.’ | 
The conglomerates at the base of the Meganos Group, division 
A, because of their peculiar character are worthy of mention. 
In the vicinity of Stewartville great angular slabs of fossiliferous 
Chico sandstone, some of them five, six, or more feet in length, 
are associated with well-rounded quartzitic and igneous bowlders. 
With them are numerous smaller limestone and sandstone pebbles, 
derived either from the Martinez or the Chico, showing that these 
beds are a true basal conglomerate. When followed to the*east 
these conglomerates thin out rapidly. 
The shales of division C of the Meganos Group are especially 
noticeable in that they are so different from anything found in the 
Tejon series on either the north or south side of Mount Diablo. 
The dark color, the calcareous lenses and nodules, the surface 
slaking into small fragments, the presence of carbonaceous material, 
and the layers of coarse sandstone which separate the different 
shale members all are similar to lithological characters of the 
OUTLINE OF EOCENE GROUPS 
Feet 
6. Clay shales with minor amount of sand- 
SCONE raise auqeie even tw de ra astcnleana aicahersltele 500 
5. Fine, buff-colored sandstone; in places 
hard, calcareous layers contain marine 
HOSSTLSUU gecesi pict ages Pica aN re IAL 175 
4. Sandy shales; exposures poor; soil very 
TREO yo Ea eter LOE SNA Ges PRO a5) 
3. Light gray to white, angular-grained 
Tejon Group sandstones, coarse to medium in tex- 
ture; cross-bedding common, with 
minor layers of chocolate-colored 
shales; twoimportant coallayers..... 75-400 
2. Chocolate-colored shales, ashy in places, 
with thin lenticular layers of coarse 
sandstone; coal layer locally known 
as blackeD iamondayeimaa een eee 50 
TA COMPLOIMERALE HM Telpre te rr ayiee palin Aenea 0-20 
Unconformity 
tR. E. Dickerson, ‘Fauna of the Martinez Eocene,” Univ. Cal. Pub. Bull. Dept. 
Geol., Vol. VIII (1914), No. 6, p. 71. 
