1915] 



Clark: Fauna of the San Pablo Group 



459 



cene of Middle California both in outline and in sculpturing. The 

 radial ribbing on M. multiradiatus is much finer and closer together 

 than on M. gabbi; also, on the former the anterior end extends much 

 further beyond the beak than on the latter. M. multiradiatus is found 

 in the Lower Miocene (Vaqueros) of Stone Canon, Monterey County, 

 and it is probably characteristic of that horizon. 



Dimensions. — Greatest antero-posterior diameter, 71 mm. ; width 

 of shell as measured from point of angulation, 30 mm. 



Occurrence. — A very common form in the lower and upper San 

 Pablo Group ; also found in the Scutella breweriana zone. 



CYEENA (COEBICULA) CALIFOENICA Gabb 

 Plate 56, figure 2 

 Gabb in speaking of this species says : 



This species is the most variable in outline of any fossil I have seen in 

 California except the oysters and similar shells. No two specimens have the same 

 shape and by selecting a suitable series, differences enough could be found to 

 make three or four species, sufficiently distinct on paper. The large number 

 of specimens, however, at my disposal, show conclusively that all belong to but 

 one species. 



C. calif omica is very abundant at one horizon near the top of the 

 San Pablo Series on San Pablo Bay. Here it is just as variable as at 

 Kirker Pass, whence it was first described ; it is associated everywhere 

 with genera that may have a brackish-water habitat. On San Pablo 

 Bay it is associated with the following species : Mytihis perrini, n. sp., 

 Bittium pabloensis, n. sp., Ceritldum rodeoensis, n. sp., Mya dickersoni, 

 n. sp., and Macoma pabloensis, n. sp. At Kirker Pass C. calif omica is 

 associated with Littorina pittsburgensis and Trophon ponder osum. 



Occurrence. — Upper San Pablo, University of California localities 

 1617, 1942, 1482, 59, 147, 1198. 



DOSINIA (DOSINELLA) AENOLDI, n. sp. 

 Plate 51, figures 1 and 2 

 Shell large, tumid ; beaks fairly prominent ; base broad ; anterior 

 extremity rather strongly produced and regularly rounded. Posterior 

 dorsal edge long and gently arcuate ; anterior dorsal edge long for 

 this genus, nearly straight, except just below the beak, where it is 

 slightly concave ; ventral edge regular and rather strongly rounded ; 

 posterior extremity subangulate. Lunule large, deeply impressed. 



