CRETACEOUS FOSSILS. 65 



A. RAMOSUS. 



PI. 11, Pig. 12, and 12 a; PI. 12, Fig. 12 b. 



[A. ramosus, Meek. Trans. Albany Inst., Vol. 4, p. 45.) 



Only two imperfect specimens of this species were found. They came from the 

 lower division of the California Cretaceous, at Cottonwood Creek, Shasta County. 

 Mr. Meek, to whom I sent a sketch, says that it "agrees with A. ramosus, except 

 in some details of the septa, which are probably not specific." 



A- IIOFFMANNII, 11. S. 

 PI. 11, Fig. 13, and 13 a; PI. 12, Fig. 13 b. 



Shell robust ; whorls five or more, enveloping about one-half, 

 abrupt, but rounded on the umbilical edge, somewhat flattened 

 on the side, rounded on the dorsum. Umbilicus nearly half the 

 diameter of the shell, shallow. Surface marked by slightly 

 sinuous ribs, and by an indefinite number of constrictions. There 

 are nine of these on the last volution of the specimen figured, 

 while on another there are but six in the same space. 



Septum: Dorsal lobe divided nearly half its length into two 

 branches, each with a long and a short branch on the outer side ; 

 and with one long branch above on each side. Dorsal saddle 

 twice as wide as the lobe; deeply bifurcate, each branch divided 

 into two double spurs. Superior lateral lobe longer than the 

 dorsal, with three spurs at the end and one above, on each side. 

 Lateral saddle of the same pattern as the dorsal, but smaller. 

 Inferior lateral lobe like the superior lateral, but not more than 

 half as large. Three supplementary lobes, nearly plain, and with 

 their saddles bifurcate. 



Figure, two-thirds of natural size. One fragment before me must have be- 

 longed to an individual of at least ten inches in diameter. 



Locality: Horsetown, Shasta County. (Div. A.) 



The septum of this species is very much like that of A. Ncwberryanus, Fig. G; 

 but while it differs in some trifling details, the external forms of the shells are 

 very distinct. A. Newberryanus is a very much flatter shell, at all ages, and the 

 umbilicus is always small, compared with the width of the shell, while in this it 

 is nearly half of the largest diameter. 

 tal. vol. I. — 9 





