110 THE CHICAGO ACADEMY OF SCIENCES. 



were sent, regards them as distinct from his A. haldcmani, but they 

 are too imperfect to admit of an accurate description of their charac- 

 ters." (Whiteaves.) 



TYPE : Canadian Geological Survey. 



HORIZON : St. Mary River series, Laramie, Cretaceous Period. 



LOCALITY : North or second branch of Milk River, Alberta. 



REMARKS : This indeterminable Lymnaeid may prove to belong to 

 White's auriculoid genus Tortacella. As its generic affinities are un- 

 certain, it is included here. 



Lymnaea Sp. 



Limnaa sp.f STANTON and KNOWLTON, Bull. Geol. Soc. Amer., VIII, pp. 

 131, 135, 1897. STANTON, Proc. Wash. Acad. Sci., XI, p. 244, 1909; 1. c. XI, p. 

 260, 1909. KNOWLTON, Proc. Wash. Acad. Sci., XI, p. 227, 1909. 



HORIZON : Ceratops beds, Laramie, Cretaceous Period. 



LOCALITY: One and one-half miles south of U-L ranch, Con- 

 verse County, Wyoming; northeast of George Moore's ranch, Section 

 16, Township 6, Sweetgrass County, Montana. 



REMARKS: This Lymnaeid has not been identified, so far as 

 known, and its generic affinities are of course unknown. 



Lymnaea Sp. Plate XVII, figure 3. 



Limncea? WHITE, Bull. U. S. Geol. Surv., 34, pp. 11, 22, pi. 2, fig. 13, 1886. 



"A single imperfect example was found at the Wales locality, 

 which evidently belongs to the genus Limncea and the general aspect of 

 which is like that of the living species, L. columella. No species of 

 Limn&a is yet known from either the Laramie or the Wasatch Group, 

 to which this form can be properly referred; but it is possible that 

 it is only a variety of the L. similis of Meek, from the Bridger Group 

 of Southern Wyoming. This specimen is too imperfect to allow of a 

 satisfactory specific description" (White). 



HORIZON : Wasatch formation, Lower Eocene Period. 



LOCALITY: Wales, Utah. 



REMARKS : Dr. White compares this Lymnseid with the recent 

 columella, but it seems to be more nearly like some species of the re- 

 cent catascopium group, and hence a Stagnicola. It also seems quite 

 different from Meek's similis. What its true affinities really are can 

 only be accurately determined by the study of additional material. 



Acella haldemani (White). 



Acella haldemani WHITE, Bull. U. S. Geol. Surv. Terr., IV, p. 714, 1878 = 

 Tortacella haldemani, a genus of Auriculidse. 



Bear River formation (Cretaceous). 



