302 ROY E. DICKERSON 



strata were being formed. In other words, minor unconformities 

 are here present. Sixty miles east of Mount Diablo there is a ten- 

 foot seam of coal at lone in the type section. Now if Clark is 

 right in correlating the lone with his Meganos group, then the 

 Meganos group is again broken by an unconformity, since several 

 hundred feet of Eocene sediments underlie the lone coal seam 

 which rests unconformably upon them. 



Along the foothills of the Sierra Nevada in the undisturbed, 

 nearly horizontal Eocene beds many interesting data are yet to be 

 secured, as here the old Eocene shore is traceable and the streams 

 of the old Eocene peneplain are still preserved beneath thick lava 

 for the inspection of some untiring geologist interested in recon- 

 structing the past of this wonderful land. 



