70 



Sierra Club Bulletin 



tained its principal characteristics unaltered down to the pres- 

 ent time is that magnificent belt of soil upon which all the ma- 

 jestic forests of the Sierra are growing. It stretches along the 

 west flank of the range like a smooth-flowing ribbon, waving 

 compliantly up and dov/n over a thousand hills and hollows, at 

 an elevation of from four to seven thousand feet above the 

 level of the sea. In some places it is more than a hundred feet 

 deep and twenty miles wide, but it is irregular as a sun-wasted 

 snow-wreath both in width and in depth, on account of the 

 configuration of the surface upon which it rests, and the vary- 

 ing thickness and declivity of the ice-sheet at the period of its 

 deposition. The long weathering and the multitude of storm- 

 washings to which it has been subjected have made its outlines 

 still more indefinite and variable. Furthermore, its continuity is 

 interrupted at intervals of fifteen or twenty miles by the river 

 cafions which cross it nearly at right angles. For, at the period 

 of the deposition of the main soil-belt as a terminal moraine of 

 the ice-sheet, long finger-like glaciers extended down every one 

 of these canons, thus effectually preventing the continuance of 

 the main terminal moraine across the canon channels. 



The method of the deposi- 

 tion of broad belts of termi- 

 nal - moraine soil will be 

 made plain by reference to 

 Figure i, which represents a 

 deposit of this kind lying at 

 the foot of Moraine Lake, 

 made by the Bloody Cafion 

 glacier in its recession to- 

 v/ard the period of its ex- 

 tinction. A A are the main 

 lateral moraines extending 

 from the jaws of the canon 

 out into the Mono Plain; I, 

 2, 3, 4, 5, 6 are concentric 

 belts of terminal - moraine 

 soil deposited by the glacier 

 in its retreat. 



These soil-belts, or fur- 



