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TERTIARY FAUNA OF FLORIDA 



From the fine-grained Miocene shales of Santa Barbara County, Cali- 

 fornia. 



This is a beautiful thin, flat species, resembling a young Patinopccteii, but 

 more oblique and oval, the left valve showing nine or more low, wide, smooth 

 ribs in the middle of the disk, with wider smooth interspaces, and the sculp- 

 ture obsolete towards the ends and base of the valve ; the right valve has 

 narrower, sharper, smaller, and more numerous riblets ; the left valve meas- 

 ures about forty-seven millimetres in height and width, and the shell was 

 apparently about ten millimetres in diameter; the ears are plain and unequal. 

 Conrad's figure is very poor and gives little idea of the shell. This may 

 belong to the section Aiqidpecteii. 



Species which may be of Miocene or Pliocene age and were collected on 

 Cerros Island, Lower California, were described by Gabb (Pal. Cal., ii., p. 32, 

 1866). P. cerrosensis Gabb {op. cit., p. 32, pi. g, figs. 55, 55 «) has eighteen to 

 twenty flattish, entire ribs, with about equal interspaces. It is of the type of P. 

 eboreus Conn, but much larger. P. Veatcliii Gabb {op. cit., p. 32, pi. 10, fig. 56) 

 is of the general type of P. nodosiis, and has about fourteen feebly nodose broad 

 ribs, striated, reticulated, and minutely squamose. The little, smooth P. Pcck- 

 hami Gabb with Camptonectes striation (Pal. Cal., ii., p. 59, pi. 16, figs, ig, 19 a, 

 1866) and the concentrically undulated P. pedroaiuts (Trask) Gabb {Plagiostonia 

 pedrodna'Yxz.sV, Proc. Cal. Acad. Sci., i., p. 86, pi. iii., fig. i, 1856; + P. anmdatiis 

 Trask, loc. cit., fig. 2, and P. inincata Trask, fig. 3; Gabb, Pal. Cal., ii., p. 60, 

 1866) comprise the remaining species of the Pacific coast, which are supposed 

 to be of Miocene age. Some of them may also prove of Pliocene age. 



The following undetermined forms have been observed in the collection 

 of the State University at Berkeley, California : 



Pccteii sp. A species in the State University collection at Berkeley, Cali- 

 fornia, which had been marked P. pahlocnsis by Dr. Cooper is evidently 

 distinct ; it has fifteen primary ribs on the left valve, many of them unevenly 

 divided near the basal margin by a shallow sulcus ; in the interspaces are low, 

 rounded riblets, extending about half way up the disk; right valve some- 

 what more convex; the ears subequal and vertically striated. Alt. 85, lat. 90 

 mm. Found in the Miocene of Foxin's Ranch, California. 



Pccten Hecnnanni Conr. var. ? A large species from Santa Inez Canon, 

 Santa Barbara County, California, is biconvex, with sixteen large, nearly 

 smooth ribs in the right valve, with subequal interspaces, in the middle of 

 each of which is a single small raised thread ; ears subequal, the posterior 



