FRESH-WATER MOLLUSKS. 81 



And now the railroad leaves the river, for the 

 canon is too deep and too narrow for river and 

 road both, and the train creeps upward over the 

 crookedest line in the country, till we stop 

 at Sisson, right at the foot of the grand 

 old mountain. 



It is almost noon now, and the sun is 

 shining full on the great white fields of 

 snow that lie above the line of green 

 woods. Here we will stop and stay for a few 

 weeks, and every day we shall be getting better 

 acquainted with Mount Shasta. 



We will watch it in the morning, and at sunset, 

 and by moonlight. We will gather flowers at its 

 base and explore its green forests, and even climb 

 far up into the perpetual winter of its glaciers. 



Then we shall begin to understand that if there 

 were no Shasta, there would be no Sacramento, 

 and that from those vast fields of 

 snow and ice come the pure streams 

 i of water which all the summer long 

 'flow joyously down to the parched 



Figure 35. valleys, carrying health and prosper- 

 ity as they go. 



"But what," you may ask, "has all this to do 

 with shells?' 7 In one sense it has everything to 

 do with them; for the melting snows fill the 



W.S.R. VOL. 86 



