110 



THE NAUTJLUS. 



rocky wall of the mountains, making boaiatiful little cascades. The 

 first of these, beginning next the j)lain, appears to come out of the 

 rocks high up, flows through a small canon between the cliifs, and 

 shortly afterward disappears in the loose talus below. Earlier in the 

 year these loose, talus rocks are wet with melted snow, but at the 

 time of collecting, in July, they were hot and dry. 



On the talus below the first fall, shells were found abundantly. 

 On the talus of the ravine, a few feet to the west, only a few were 

 found, while still further west none whatever could be found any- 

 where. This little stream from the mountain, therefore, seems to 

 mark its distribution on the mountain towards the west. Acting on 

 this basis, the rocks were followed upward along the sides of the 



mountain, following the little gully of the stream mentioned. Shells 

 were found as high as we went, a distance of 1,500 feet, or up to a 

 total elevation of 5,000 feet above the sea. Time did not permit a 

 search higher. 



The limit of distribution of the shells, as mentioned, ends abruptly. 

 A search eastward from the mountain stream caused the discovery of 

 shells in abundance for a mile; beyond this we did not go. There 

 is a great deal of difficult mountain climbing necessary to explore 

 these regions, and a half day does not permit one to go far. But 

 from the fact that they have been found on the slopes of Mt. Mc- 

 Donald, across the lake to the south, it would appear evident that the 

 unexplored canons and mountain sides forming the large amphithea- 

 ter supplying the lake's waters, support the Pyramidulas. 



The writer has been in different places in the Mission range, from 

 one end to the other, on the western slopes, and nowhere else have 



