1913] Dickerson: Fauna of Eocene at Marysville Buttcs 287 



sheet 2y» miles N.W. of Grayson Creek on main road from Mar- 

 tinez to Walnut Creek, north side of road." It is associated with 

 Conus hornii, Turritella uvasana, Rimella canalifcra, Cylichna 

 costata, Dentalium cooperi, Cardium breweri, Modiola ornata, 

 Meretrix hornii, Cardita, sp., Tapes conradiaiia, and Trochocy- 

 athus striatus ( ?). Cooper figures a "young" form of Oliverato 

 which proves to be a new species, Caricella stormsiana. 



ARCHITECTONIC A WEAVERI, n.sp. 

 Plate 13, figures 2a and 26 



Whorls five or six, low, conical. The last two whorls are 

 decidedly concave and are marked by two nodose carinae, one 

 immediately above a sharp linear suture and the other just below. 

 The nodes on the upper carina are much closer together than 

 those on the lower. The upper nodes have a beaded appearance 

 while the lower nodes are distinctly elongated and extend nearly 

 to a revolving line in the middle of the smooth concave portion 

 of the whorl. 



A single specimen was found at University of California 

 Locality 1853. 



This form is readily distinguished from A. cognata and A. 

 hornii by its concave whorls and distinctive decoration. Named 

 in honor of Professor C. E. Weaver, University of Washington. 



Dimensions: Height, 7mm; radius, 10mm. 



CARICELLA STORMSIANA, n.sp. 

 Plate 13, figures 3a and 3b 



Shell pyriform, thin, smooth, spire low; whorls number six. 

 The first three nuclear whorls smooth and more convex than the 

 fourth and fifth whorls. Body-whorl twice as long as spire ; 

 upper part swollen and smooth while lower part is marked by 

 eight or nine revolving transverse riblets. Outer lip, simple. 

 Canal short and slightly twisted. At least two strong plaits 

 appear on the lower part of the columella. 



Cooper described this as a young form of Ancilla (Oliverato) 

 calif ornica, but the plaits on the columella throw it entirely out 

 of this subgenus. 



