1917] Nomland: Fauna of the Santa Margarita Beds 



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yellowish-brown color and has a thickness of about fifty feet. The 

 basal conglomerate, containing numerous specimens of Ostrea titan, 

 overlies serpentine of Mesozoic age in which are numerous Pholas (?) 

 borings. A light-colored cherty shale rests conformably on the sand- 

 stone. The invertebrate fauna consists of the following identifiable 

 forms : 



Santa Margarita Fauna at Base of ' ' Monterey ' ' Shale 

 Astrodapsis tumidus Eemond Pliaeoides annulatus (Keeve) 



Mytilus, sp. Pholas('?), sp. 



Ostrea titan Conrad Psammobia, sp. 



Pecten crassicardo Conrad Spisula, sp. 



Pecten crassicardo biformatus, Tamiosoma gregaria Conrad 



n. var. 



In the northeastern part of the San Luis quadrangle a fauna has 

 been collected 20 in a coarse white calcareous sandstone. The preser- 

 vation of the fossils is very poor and usually only molds and casts 

 are present. On comparison of this fauna with that of the upper 

 San Pablo, a close relationship is apparent. The fauna from this 

 locality, the type section of the Santa Margarita formation, was 

 identified as follows : 



Santa Margarita Fauna from the Type Section 



Eehinodermata Pholas, sp. 



Astrodapsis margaritanns Psammobia, sp. 



Kew (MS) Saxidomus nuttalli Conrad 



Astrodapsis tumidus Eemond Schizothaerus nuttalli Conrad 



Astrodapsis whitneyi Eemond Solen, sp. 



Bryozoa Tellina, sp. 



Two species Tivela, sp. 



Pelecypoda Gastropoda 



Area trilineata Conrad Astralium raymondi Clark 



Cardium quadrigenarium Con- Bulla, sp. 



rad Calyptraea martini Clark 



Cardita, sp. Calyptraea, sp. 



Chione, sp. Chrysodomus, sp. 



Glycimeris, sp. Crepidula, sp. 



Maeoma, sp. Murex, sp. 



Metis alta (Oonrad) Nassa, sp. 



Mytilus, cf. coalingensis Natica, sp. 



Arnold Olivella, sp. 



Ostrea titan Conrad Trophon, sp. 



Ostrea, sp. (small) Turritella freya, n. sp. 



Paphia, sp. Turritella margaritana, n. sp. 



Panope generosum Gould Cirripedia 



Pecten estrellanus Conrad Tamiosoma gregaria Conrad 



Pecten raymondi Clark Pisces 



Phacoides nuttalli (Conrad) Shark teeth 



20 At several localities on Santa Margarita Creek and Trout Creek, near the 

 town of Santa Margarita, San Luis quadrangle. Type section of the Santa 

 Margarita formation. Collected by E. E. Dickerson and W. Gordon. 



