160 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4th Se«. 



Gld., Pecten andersoni Am., P eaten crassicardo Con.. Pecten 

 discus Con., Pecten estrellamis Con., Pecten hamlini Arn., 

 Pecten lompocensis Arn., Pecten miguelensis Arn., Pecten 

 nevadanus Con., Pecten peckhami Gabb, Pecten perrini Arn., 

 Pecten propatulus Con., Phac aides acntilineatns Con., P/ior- 

 coides richthofeni Gabb, Phacoides sanctcecrucis Arn., Pinna 

 alamedcnsis Yates, Septifer coalingensis Arn., Tellina idee 

 Dall, Thracia trapesoidea Con., Tivela inezana Con., Yoldia 

 impressa Con., Yoldia oregona Shum., Yoldia submonterey- 

 ensis Arn., Zirphea dentata Gabb, Agasoma barkerianum 

 Cooper, Bathytoma keepi Arn., Cancellaria condoni And., 

 Cancellaria dalliana And., Cancellaria vetusta Gabb, Chrysodo- 

 mus nodiferiis Con., Conns hayesi Arn., Conns owenianus 

 And., Crepidula princcps Con., Fin<.y kernianiis Cooper, FiCM.y 

 nodiferiis Gabb, FiVm^ pyriformis Gabb, Hemifusns zvilkesea- 

 nus And., Macron merriami Arn., Molopophorus anglonana 

 And., Nassa arnoldi And., Neverita callosa Gabb. Ranella 

 mathewsoni Gabb, Sinum scopidosiim Con., Terebra cooperi 

 And., Thais prcecursor Dall, Trochita costellata Con., Trophon 

 carisaensis And., Trophon gabbianus And., Trophon kernensis 

 And., Tnrritella ocoyana Con. 



This faunal horizon has been called by Dr. J. C. Merriam 

 the Agasoma zone, but this name is given up, since the genus 

 Agasoma is not confined to the zone ; and the original Agasoma 

 beds have been shown by Dr. B. L. Clark to be Oligocene. 



This fauna is tropical or subtropical, and indicates a tempera- 

 ture considerably warmer than that of southern California at 

 present, as shown by the presence of Chione, Dosinia, Lyro- 

 pecten, giant Area, Ficus, Trophon, Conns, Pinna, and giant 

 Turritella, all tropical types. 



Vaqueros. This formation was first named by H. W. Fair- 

 banks, ^* from the outer Coast Ranges, in the region of San 

 Luis Obispo, California. It was afterwards recognized by 

 R. Arnold^^ at numerous localities in the outer Coast Ranges of 

 middle California, and in the Santa Ynez Mountains of 

 southern California. 



"U. S. Geol. Survey, San Luis Folio (1904), No. 101. 



ssprof. Paper 47, U. S. Geol. Survey, (1906); Bull. 309, U. S. Geol. Survey, 

 (1907); Proc. U. S. Nat. Mus., vol. 34, No. 1617, (1908), pp. 343-389; and Environ- 

 ment of the Tertiary faunas of the Pacific Coast of the United States, Jour. Geol., 

 vol. 17, (1909), pp. 509-533. 



