86 PALAEONTOLOGY OF CALIFORNIA. 



ribs, crossed by numerous fine revolving ribs, sometimes showing 

 a tendency to alternation in size, especially on the anterior part 

 of the shell. 



This shell docs not appear ever to attain so large a size as either of the preced- 

 ing species. 



Figures, natural size, and magnified. 



Localities: Clayton; Cochran's, near Mount Diablo; and Alizos Creek, near 

 Fort Tejon. 



Subgen. HEMLFUSUS, Swains. 

 F. (H.) Hornii, n. s. 



PI. 28, Fig. 206, and 206 a. 



Shell unequally fusiform; spire low, tapering concavely. 

 Whorls six, the last bi- or tricarinate; the others with one 

 rounded carina, except the one or two forming the extreme 

 apex, which are rounded, smooth, and without markings. Mouth 

 biangular above, gradually narrowing below; canal straight. 

 Surface marked by two or three series of prominent tubercles, 

 connected longitudinally by acute ribs, which are prolonged 

 above to the suture, and below to irregular distances, becoming 

 gradually obsolete. 



Between these are numerous linear, revolving ribs, which 

 rarely cross the longitudinal ribs. In addition to these are 

 numerous fine lines of growth. 



The upper whorls are merely cancellated. 



Figures, natural size and magnified. 

 Locality : Near Fort Tejon. 



Named after Dr. Geo. H. Horn, who collected all the specimens I have seen of 

 this, the prettiest species of California Cretaceous Fusus. 



F. (H.) Coopebii, n. S. 



PI. 28, Fig. 207. 



Shell of nearly the same outline as the preceding, except that 

 the spire is a little higher, and tapers convexly ; whorls six, in 



