IS 



PLATE I 



Figures 1-3. Oreohelix cooperi limitaris (Dawson). Series of three specimens from Waterton 

 lake, Alberta; natural size. (Geol. Surv., Can., Cat. No. 2881.) 



Figure 4. Oreohelix cooperi limitaris (Dawson). Immature specimen from Waterton lake, 

 Alberta; natural size. (Geol. Surv., Can., Cat. No. 3144.) 



Figure 5. Oreohelix cooperi limilaris (Dawson). Specimen shown in Figure 1; x 2. 



Figure 6. Oreohelix strigosa canadica n. subsp. The type specimen from Donald, B.C.; natural 

 size. (Geol. Surv., Can., Cat. No. 2882.) 



Figure 7. Oreohelix strigosa canadica n. subsp. Same specimen; x 2. 



Figure 8. Gonyodiscus shimekii (Pilsbry). Specimen from Kananaskis, Alberta; x 6. (Geol. 

 Sun-., Can., Cat. No. 2937). 



