\'0L. VII] WARING— STRATIGRAPHIC AND FAUNAL RELATIONS 69 



and are crossed by distinct spiral ribs which also cover the 

 canal. Aperture elongated, widest above and tapering down 

 to the canal. Locality 2. L. S. J. U. Pal. Coll. 



Turritella chicoensis Gabb 

 PI. 9, Fig. 12 

 Shell variable in size, elongate; number of whorls variable 

 with age, usually about nine; whorls rounded and sometimes 

 flattened on upper half; ornamented by six or seven spiral 

 ribs; between which are minute spiral lines; suture deep; 

 under surface of body whorl slightly convex and usually 

 marked by fine revolving lines. Locality 2. L. S. J. U. Pal. 

 Coll. 



Cephalopoda 



Baculites chicoensis Trask 

 PL 9, Fig. 11 

 Baculites chicoensis Trask, Proc. Cal. Acad. Nat. Sci., vol. 



1, pt. 2, p. 93, pi. 2, fig. 2, 1856, Chico Creek, Cal. 



Shell elongated, slightly tapering, section ovoid, dorsal side 

 narrowest; sides ornamented by curved ribs with convexity 

 downwards and longest limb on the dorsal side ; under surface 

 marked by septae which may be seen in the figure. The 

 mouth and lower part of the specimen are missing. Locality 



2. L. S. J. U. Pal. Coll. 



Hauericeras transitionale, new species 

 PI. 9, Fig. 15 



Shell compressed, nearly circular; whorls six, abruptly de- 

 pressed at the umbilical margin; venter keeled; surface 

 smooth with five broad transverse grooves to a revolution; 

 these grooves turning slightly forward at the umbilical mar- 

 gin and backward on the back. Locality 2. L. S. J. U. Pal. 

 Coll. 



This species seems very close to Ammonites gardeni 

 Stoliczka^^ H. gardeni Baily" differs by having closely spaced 

 sickle-shaped lines of growth. 



H. transitionale is confined to the upper shales of the Chico 

 formation. 



^Ammonites gardeni Stoliczka, 1865, Cret. Cephal. S. India, p. 61, pi. 33, fig. 4. 

 " Quat. jour. Geol. Soc. Lon., vol. 11, p. 156, pi. 11. fig. 3. 



