26 THE MOUNTAINS OF CALIFOBNIA 



fest in their forms and trends and general char 

 acteristics the same subordination to the grinding 

 action of universal glaciation as to their origin, and 

 differ from the islands and banks of the fiords only 

 in being portions of the pre-glacial margin of the 

 continent more deeply eroded, and therefore covered 

 by the ocean waters which flowed into them as the 

 ice was melted out of them. The formation and 

 extension of fiords in this manner is still going 

 on, and may be witnessed in many places in Glacier 

 Bay, Yakutat Bay, and adjacent regions. That the 

 domain of the sea is being extended over the land 

 by the wearing away of its shores, is well known, 

 but in these icy regions of Alaska, and even as far 

 south as Vancouver Island, the coast rocks have 

 been so short a time exposed to wave-action they 

 are but little wasted as yet. In these regions the 

 extension of the sea effected by its own action in 

 post-glacial time is scarcely appreciable as compared 

 with that effected by ice-action. 



Traces of the vanished glaciers made during the 

 period of greater extension abound on the Sierra 

 as far south as latitude 36. Even the polished 

 rock surfaces, the most evanescent of glacial rec 

 ords, are still found in a wonderfully perfect state 

 of preservation on the upper half of the middle 

 portion of the range, and form the most striking 

 of all the glacial phenomena. They occur in large 

 irregular patches in the summit and middle regions, 

 and though they have been subjected to the action 

 of the weather with its corroding storms for thou 

 sands of years, their mechanical excellence is such 

 that they still reflect the sunbeams like glass, and 



