126 PROCEEDINGS OF THE ACADEMY OF [Feb., 



8 shells have 1 lamella, the axial. 



5 shells have 2 lamellae, axial and superior. 



PI. XIII, figs. 1, 2, Station 4, northwest branch of ravine back of 

 Gardner's Mine, about three-quarters of the distance to summit. 

 Some of the shells have the terminal cone slightly shorter than in the 

 types. Sculpture variable, as shown in the figures. Internal lamellae 

 1 , 2 or 3. In 20 specimens opened : 



10 have 1 lamella, the axial. 

 8 have 2 lamellae, axial and superior. 

 2 have 3 lamellae, axial, superior and basal. 



Below Station 5, pi. X1I1, figs. 13, 14. The shells are small and 

 ribbed throughout, rarely over 9 mm. long. 



Box Canyon. — In the Box Canyon, at two stations, one some dis- 

 tance below Station 5 (pi. XIII, figs. 6, 7, 8), the other at the mouth of 

 Indian Creek, the shells are long and slender, strongly ribbed throughout. 

 Axial and superior lamellae are present in a few opened. 



Length 13, diam. 3.2 mm.; whorls 14. 

 10, " 3.2 " " m. 



Station 8. — A small series agrees, at least superficially, with those 

 from Station 14, which lies about 800 feet lower. 



Station 14. — The shells do not differ much from the type lot. There 

 is a longer and coarsely ribbed and a shorter, more closely ribbed, 

 form. Of the longer form we opened 10 shells, 1 having three, 4 two, and 



5 one lamellae. In seven of the shorter form opened 1 has two lamellae, 



6 have one lamella. 



Forms from head of Onion Creek. — Two forms are represented in 

 the small lot examined. PL XIII, fig. 9, shows a slender shell with 

 coarse, very widely spaced ribs: length 12, diam 3.3 mm., whorls 12^. 

 It has one lamella, the axial. PL XIII, figs. 10, 11, 12, represents the 

 prevalent form, shorter than the preceding, very finely and closely 

 ribbed throughout, or the ribs may be weak or subobsolete on the 

 penultimate next preceding whorls. In five opened, only the axial 

 lamella is present. 



Length 10.5, diam. 3.5 mm.; whorls 11^. 

 9.5, " 3.3 " " 10i 



Jhu Canyon. — At the head of Jhu Canyon a gathering consists of 

 two forms, similar to pi. XIII, figs. 9-12, from Onion Creek. The 

 larger form is near typical intermedia, but the smaller may represent 



