86 OUR NATIONAL PARKS 



cannot be the work of avalanches, because the 

 striae show that the agent, whatever it was, flowed 

 along and around and over the top of high ridges 

 and domes, and also filled the deep canons. 

 Neither can they see how water could be the 

 agent, for the strange polish is found thousands 

 of feet above the reach of any conceivable flood. 

 Only the winds seem capable of moving over the 

 face of the country in the directions indicated by 

 the lines and grooves. 



The pavements are particularly fine around 

 Lake Tenaya, and have suggested the Indian 

 name Py-we-ack, the Lake of the Shining Rocks. 

 Indians seldom trouble themselves with geologi- 

 cal questions, but a Mono Indian once came to 

 me and asked if I could tell him what made the 

 rocks so smooth at Tenaya. Even dogs and 

 horses, on their first journeys into this region, 

 study geology to the extent of gazing wonder- 

 ingly at the strange brightness of the ground, 

 and pawing it and smelling it, as if afraid of 

 falling or sinking. 



In the production of this admirable hard finish, 

 the glaciers in many places exerted a pressure of 

 more than a hundred tons to the square foot, 

 planing down granite, slate, and quartz alike, 

 showing their structure, and making beautiful 

 mosaics where large feldspar crystals form the 

 greater part of the rock. On such pavements 

 the sunshine is at times dazzling, as if the sur- 

 face were of burnished silver. 



