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IOQ3 



TERTIARY FAUNA OF FLORIDA ^ '^ 



scribed as having twenty-two ribs and being subtruncate behind, but has not 

 been recognized since, and may be a young Fragnin or a small species of the 

 present group. It is said to have been collected from the Miocene of the San 

 Diego Mission, though no Miocene is known at present in this vicinity. It is 

 not the Cardiiim modestuin of Adams and Reeve, " Zoology of the Sama- 

 rang," 1850. 



On the Pacific coast in the Pliocene and later we have several fine species. 

 Chief among these is Cardiuiii corbis, Martyn, 1784 (C. Nnttallii Conrad, 

 1838, -|- C. calif orniannm Conrad, 1838, -f- C. N uttallianuin Carpenter, 1864). 

 This species ranges from the Pliocene to recent seas in time, and at present 

 from Bering Sea to Monterey and from California to Kamchatka. Another 

 is C. calif orniense Deshayes, 1839 (+ C". pseudofossile Reeve, 1844, + C. 

 hlandum Gould, 1850) , a more triangular and less inflated species with forty 

 to forty-eight rounded, nearly smooth ribs, which is recorded from the Plio- 

 cene and Pleistocene of California and ranges in the recent state from North 

 Japan to Bering Sea and south to Monterey, California. In the bowlder clays 

 of Vancouver Island a variety of this species has been found by Dr. Newcombe 

 in which the ribs are much depressed and flattened, and the interspaces reduced 

 to narrow, shallow grooves. This may take the name of var. comoxense Dall. 

 It reaches about forty millimetres in length. 



Cardium (Cerastoderma) ■waltonianum n, sp. 



Plate 48, Figure 19. 



Oligocene (?) of Flournoy's mill-race at Summerville, two miles east of 

 Argyle Post-Office, Walton County, Florida; L. C. Johnson. 



Shell solid, coarse, strong, elevated, short, with about forty narrow, flat- 

 topped radial ribs separated by subequal channelled interspaces crossed by 

 lines of growth; a narrow, smooth area on the hinge-margin on each side 

 of the high, rather pointed beaks; hinge very strong; internal basal and 

 anterior margins with short flutings. Lon. 45, alt. 45, diam. 28 mm. 



This shell is more trigonal than C. craticuloide and has less elevated ribs ; 

 it is not so produced at the ends as C. leptopleura Conrad, has narrower and 

 more crowded ribs and a dififerent outline. 



Cardium (Cerastoderma) pansatrum n. sp. 

 Plate 40, Figure 14. 

 Oligocene of Walton County and of the Oak Grove sands, Santa Rosa 

 County, Florida ; Johnson and Burns. 



