1917] Nomland: Fauna of the Santa Margarita Beds 299 



Feet 



Hard grayish-brown sandstone; grains moderately well-rounded with 



pebbles of volcanic rocks 13 



Barnacle reef, with arkose sand and large number of specimens of 



Balanus 1 



Coarse, light-gray, pebbly sand with calcareous cement; pebbles sub- 

 angular, chiefly andesite, quartz, and feldspar ; fauna includes Astro- 



dapsis amoldi, Ostrea vespertina 30 



Incoherent fossiliferous sand with large number of well-preserved speci- 

 mens of Mytilus Tcewi 38 



Bed of Ostrea titan in ashy sand 1 



Fine ashy sand 25 



Tuffaeeous sand with Ostrea titan 1 



Fine ashy sand with grains of quartz and feldspar 19 



Ostrea titan in tuffaeeous sand 1 



A very persistent bed of bluish-gray water-laid volcanic ash. Unaltered 

 feldspar, hornblende, and quartz ; also volcanic type of biotite. All 



grains angular and broken 25 



Unconsolidated gray sand consisting essentially of quartz, feldspar and 



biotite 19 



Eeef with numerous specimens of Ostrea titan 3 



Very fine-grained arkose sand interstratified with layers of rhyolitic ash ; 



has large number of crab borings 25 



Bed consisting largely of shells of Ostrea titan 3 



Fine gray sand with minute rounded grains of serpentine 57 



Highly fossiliferous conglomerate composed mostly of shells of Ostrea 



titan, Tamiosoma gregaria, Pecten estrellanus 2 1 /2 



Incoherent buff to brown arkose sand with minute fragments of ser- 

 pentine 30 



Basal coarse to medium-grained sand with well-rounded pebbles of 

 serpentine ; matrix chiefly orthoclase, and quartz ; cemented by 

 calcium carbonate 25 



Total thickness 426% 



Vaqueros 



Big Blue serpentinous member. 



Fauna of the Santa Margarita Northeast of Coalinga 

 In the report on the palaeontology of the Coalinga district by 

 Ralph Arnold, 13 a brief Santa Margarita faunal list was included. 

 This list comprised the following species : 



Fossils from the Santa Margarita, Listed by Arnold 



Astrodapsis whitneyi Eemond Pecten crassicardo Conrad 



Cliione eonradiana Anderson Pecten estrellanus Conrad 



Cryptomya ovalis(?) Conrad Solen sicarius Gould 



Dosinia ponderosa Gray Zirphaea dentata Gabb 



Hinnites giganteus Gray Trophon carisaensis Anderson 



Macoma nasuta Conrad Tamiosoma gregaria Conrad 

 Ostrea titan Conrad 



is Arnold, Ralph, Palaeontology of the Coalinga district, Fresno and Kings 

 counties, etc. 



