/O THE NAUTILUS. 



right angles to cardinal and basal margins. Cardinal margin 

 regularly rounded anteriorly from beaks; anterior end rounded 

 into straight basal margin; posterior end, anterior end and basal 

 margin closed. Surface marked by prominent irregular lines of 

 growth following curvature of shell and extending continuously 

 along sides and on posterior end to umbones, also marked by 

 17 to 19 less prominent radiating, regularly spaced ribs that 

 cover entire surface of sides and do not extend on to posterior 

 end as in the case of the lines of growth. The radiating ribs 

 become more prominent proceeding from the anterior to the 

 posterior end. 



Dimensions. Length, 50 mm. Posterior width, 40 mm. 

 Posterior thickness, 35 mm. Greatest width and thickness at 

 posterior end. 



Notes. Named in honor of P. F. Harrigan, Los Angeles, 

 Calif. 



Type. Museum, Stanford University, Calif. 



Locality. Black shale, Western Pacific Railroad cut near 

 Altamont, Tesla Quadrangle. 



Horizon. Upper Chico, upper Cretaceous. 



ScHLOENBACHiA TEMPLETONi, n. s. Hall and Ambrose. 



Description. Shell discoidal and compressed, slightly inflated 

 on the last whorl, attains a diameter of 16 cm. Keel slight and 

 broken into nodes. Surface ornamented with about 45 (counted 

 along ventral margin) rounded, slightly curved, forward point- 

 ing ribs, that begin in narrow elongated nodes (slightly diverg- 

 ing from plane of keel) on the ventral margin and end on the 

 umbilical margin in about a third as many pointed nodes as 

 ribs, from which the umbilical walls make a perpendicular 

 descent. Some of the ribs bifurcate on the surface of the shell 

 in nodes without any apparent regularity of system and from 

 three series of costal nodes on the surface — not counting the 

 umbilical and ventral margin nodes — and run nearly regularly 

 with the curvature of the whorl. The nodes on the ventral 

 margin are opposite each other. The tubercules of the keel 

 stand a little forward of the marginal nodes in a position to 

 exactly meet the forward curving of the ribs. 



