HANNA: MIOCENE LAND SHELLS. 7 



and minor shell characters that it seems best for the present 

 to include this under Pijramidula, the genus which it most re- 

 sembles. Perhaps better material will eventually be secured 

 and enable the correct genus to be determined. The specimen 

 is not perfect. The aperture has been lost, together with the 

 shell substance of the last two whorls. It has also been 

 crushed but not in such a manner as to distort the shape. The 

 original shell had over seven whorls and was considerably 

 more elevated than the measurements given show. But the 

 diameter was but little if any greater on account of the last 

 whorl growing in beneath the one preceding. Also when the 

 shell was complete the last whorl was but little angulated on the 

 periphery, this seeming to be a character which applies only to 

 the whorls up to and including the sixth. 



It is named for the Mascall, one of the subdivisions of the 

 John Day series. 



At first it was believed that this specimen was Conrad's 

 Helix (Zonites) marginicola because it was the only form 

 found with the "spire scarcely raised above the margin of the 

 last volution." However, he states that his shell had six whorls 

 and was narrowly umbilicate. He gave no measurements, but 

 his figure shows that he had a young specimen. He states fur- 

 ther that his shell was narrowly umbilicate, a condition which 

 would not be true in the young of mas c aliens is. There is, in 

 my opinion, little doubt that one of the species subsequently 

 described under another name is marginicola, but this cannot 

 be recognized because of the inadequate original description. 

 It is to be hoped that if the type specimen is in existence it will 

 some day be fully described. 



Polygyra dalli Stearns. 



Helix (Monodon) [error for Mesodon] dalli Stearns. In "White, Bui. 18, U. S. Geol. 

 Surv., p. 14, pi. Ill, figs. 4-6, 1885. 



Polygyra dalli Stearns, Proc. Wash. Ac. Sci., vol. II, p. 655, pi. XXXV, figs. 4-6, 

 1900. Same figures as above reproduced. 



Polygyra dalli Stearns, Science, new series, vol. XY, p. 153, 1902. 



Polygyra dalli Stearns, Univ. of Calif. Pub. Geol., vol. V, No. 3, p. 67, 1906. 



One almost perfect specimen and four young and broken 

 ones were obtained at Cove Inlet, John Day river, by Mr. 

 Martin. A large number of specimens in the University of 

 California indicates that this is probably the most abundant 

 species in the region. As Stearns has shown, it is very closely 

 related to Polygyra columbiana Gould, which is common in the 



