1913] 



Louderback : The Monterey Series 



181 



GEOLOGIC COLUMN 



For Formations North of Santa Clara Valley, Ventura County 

 (According to Descriptions in Bull. 309, U. S. G. S.) 



Fernando 



Formation 

 ( Pleistocene 

 to upper 



Miocene) 



Conglomerate, sandstone, and arenac- 

 eous clay 



Unconformity 



Modelo 



Formation 

 (middle 



Miocene) 



Vaqueros 



Formation 

 (lower 



Miocene) 



Sespe 



Formation * 

 (Eocene) 



Upper shale, 

 200-1500 ft. 



Upper sandstone, 

 maximum 900 ft. 



Lower shale, 

 400-1600 ft. 



Lower sandstone, 

 200-2000 ft. 



500-600 ft. 



About 700 ft. 

 500 ft. 



About 500 ft. 



Upper Sespe, 

 500 ft. 



Middle Sespe 

 (Red beds). 

 1240-1800 ft. 



Lower Sespe, 

 400 ft. 



Topatopa 



Formation 5500 ft. exposed 

 (Eocene) 



Granular, siliceous to earthy, fissile 

 shale, brown, gray, or yellowish; 

 carrying calcareous layers and len- 

 ticular limestone concretions 



Chiefly of white subangular quartz, 

 slightly yellow by iron; much dark 

 chert in fragments also present 



Indistinguishable lithologically from 

 upper shale 



Massive, heavy bedded, white to yel- 

 lowish gray, locally gritty with 

 pebbles of dark chert and sand- 

 stone; scattered yellow weathering 

 limestone concretions, often stained 

 dark by petroleum; concretions 1-5 

 ft. in diameter, very characteristic 



Siliceous shale and limestone, gray 

 but yellow weathering, indistin- 

 guishable lithologically and faunally 

 from Modelo shale 



Deep maroon, brown and gray shale 



Gray shale 



Chiefly shale with limestone lentils 



Rusty (ochreous) to greenish gray, 

 calcareous sandstone separated by 

 bands of shale 

 Sandstone and shale, occasionally con- 

 glomerate; 400-800 ft. 

 Heavy sandstone often coarse and 

 gritty with thin shale beds, occa- 

 sionally conglomerate; 500 ft. 

 Massive sandstone, occasionallv con- 

 glomerate; 300-400 ft. 

 ^Coarse conglomerate; 40-100 ft. 

 f White sandstone and green and pink 

 L clays and shale 



/-Hard submassive sandstone and 

 quartzite, greenish gray, clear or 



; mottled with white, and shale; 

 sandstones usually light gray to 



I white 



Granite 



Unconformity 



