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University of California Publications in Geology [Vol. 13 



This species appears to differ from L. suciensis Whiteaves in the 

 less oblique character of the whorls and in its general lack of sculpture. 

 Horizon. — Chico group, Turritella pescaderoensis zone. 



Family Voltjtidae 

 Genus VOLUTODBRMA Gabb 

 VOLUTODEEMA MAGNA, n. sp. 

 Plate 37, figure 1 



Type specimen 12274, Coll. Invert. Palae., Univ. Calif., loc. 2166. 



Shell elongate, rather slender; four or more whorls; pillar slightly oblique, 

 without visible plaits; whorls of spire large, decreasing gradually in size; suture 

 appressed; conspicuously shouldered in front of the suture on the last two 

 whorls; body whorl large; outer lip expanded; aperture wide; spire apparently 

 ornamented by spiral ridges which are indistinctly nodose on the penultimate 

 whorl; body whorl ornamented by two equally prominent rows of nodes, num- 

 bering from 18 to 20, below which are two rows of less conspicuous nodes; below 

 these in turn are at least seven evenly spaced slightly nodose ridges. Length 

 of type, 95 mm.; maximum diameter of body whorl, 43 mm. 



This form resembles V. gabbi (White), but it is distinguished 

 from that species by its prominent shoulder. A cast, specimen no. 

 12278, from the same collecting locality as this new species, appears 

 to have a relatively shorter spire for the penultimate whorl appears 

 to be smaller. The expanded lip of that specimen is shown on plate 

 39. It is not certain whether this cast should be included Avith 

 V. magna ; if not, it probably represents an undescribed form that is 

 more closely related to V. gabbi. 



Horizon. — Chico group, zonal position uncertain, probably the 

 Turritella pescaderoensis zone. 



VOLUTODEEMA SANTANA, n. sp. 

 Plate 36, figure 3 



Type specimen 12294, Coll. Invert, Palae., Univ. Calif., loc. 2135. 



Shell short, thick, with more than three whorls; pillar oblique, with two 

 strong plaits, probably visible from the aperture of a perfect specimen; sculp- 

 ture of the early whorls inconspicuously marked by revolving ridges; suture 

 appressed; the slight shoulder below the suture is marked by one or two indis- 

 tinct revolving ridges; last whorl ornamented by ten equidistant srjiral ridges, 

 the first six of which are broken up into about twelve rows of axial nodes; the 

 last four ridges are rather sharp and are continuous, whereas those above become 

 almost obsolete between the strong nodes; outer lip thin, very widely expanded; 

 columella apparently without a callus; canal short. Height of body whorl of 

 the type, 50 mm. ; maximum width of body whorl, 37 mm. 



Horizon. — Chico group, Turritella pescaderoensis zone. 



