1911).] NATURAL SCIENCES OF PHILADELPHIA. l.",7 



behind the margin; anterior fasciole rather short, moderately wide, 

 emarginate at the extremity. 



Dimensions. — Altitude, 23.4 mm.; maximum diameter, 13 mm.; 

 spiral angle, 57°. 



This form is well characterized by its somewhat buccinoid outline 

 and rather low, obtuse spire, subdued spiral sculpture, the slightly 

 flaring outer lip and plicate inner lip. This species is represented 

 in the Coon Creek collection by two perfect specimens which are 

 remarkable for shells as old as the Cretaceous on account of their 

 state of preservation. The individuals possess a certain freshness 

 of appearance and shell-color that remind one of recent gastropods 

 lately recovered from the water. 



Occurrence. — Ripley Formation: Dave Weeks Place, on Cood 

 Creek, McNairy County, Tennessee. 



Family VOLUTID^E. 

 Geuns TECTAPLICA gen. nov. 



Etymology: tecta, hidden; plica, fold. 



Type: Tectaplica simplica sp. nov. 



Shell of medium size, thick and strong; rudely biconic in outline; 

 spire about one third the entire length of the shell; apex acute; 

 protoconch broken away, scar small; whorls very much appressed; 

 sculpture dominantly axial ; aperture lanceolate, produced anteriorly 

 into a slightly bent canal; outer lip simple; inner lip callous; parietal 

 wall glazed; columella marked by three weak but well-defined folds, 

 terminating far within the margin of the aperture. 



This genus is well characterized by a thick, strong and simple shell 

 which has a columella marked by feeble folds. It is one of the most 

 primitive of the Volutes and may be considered as ancestrally related 

 to Volutilithes. It differs from Volutilithes in having a less elongate 

 spire, which is flattish on the sides and not interrupted by pro- 

 nounced shoulders. Volutilithes is typically spinose and has an 

 inner lip usually well excavated and marked by prominent folds, 

 which extend well out on the inner lip. 



Tectaplica simplica sp. nov. PL XXIII, fig. 4. 



Description. — Shell of medium size, biconic in outline; spire 

 acuminate, less than one third the entire length of the shell; whorl- 

 very closely appressed. six in number on conch; axial slopes flattish: 

 protoconch broken away, -car small; external sculpture dominantly 

 axial, consisting of ten prominent broadly rounded costae increasing 

 toward the aperture, crossed by very many faint spiral ridg 



