Nature's Notes * * * * < * 101 



deposits in the streams. It gives them a gray, milky color and is called 

 glacier milk. Sometimes it is called rock flour. Mount Rainier contains 

 some of the greatest glaciers in the land. You ought to stop off and see 

 that mountain. It's a beauty and one of our most interesting mountains." 

 "Tell us some more about mountains." 



"All right. There are two kinds of mountains, those that are pushed 

 or tilted up, and those that are piled up by successive lava flows from 

 volcanoes. The Sierra Nevada was pushed up. It is tilted, the eastern 

 edge of the uplift being from twelve to fourteen thousand feet above 

 the sea and from five to eight thousand feet above the territory im 

 mediately surrounding it. The western edge is buried beneath the silt 

 of the San Joaquin Valley. Its slope on the western side is so gradual 

 that if a highway could be built from the San Joaquin to the summit of 

 Mount Lyell in a direct line, the grade would be but two per cent. Yet 

 the Sierra Nevada is supposed to be a terribly rough and rugged moun 

 tain range. It is, as a matter of fact, because of the canyons that have 

 been cut into it by streams and glaciers. On the eastern slope, the tilt is 

 almost perpendicular. It is a formidable barrier. It is explained by 

 scientists that the Sierra Nevada is a single mountain four hundred miles 

 long and eighty miles wide, the biggest mountain in the world. John 

 Muir tells of a terrible earthquake in 1872 which raised the Sierra Ne 

 vada thirty-two feet. This was a tremendous upheaval, but you can imag 

 ine how puny it must have been compared to the original upheavals which 

 pushed the whole mountain, eighty miles wide and four hundred miles 

 long, out of the earth, making a brand new mountain of solid granite. 



"Mount Rainier, on the other hand, is an example of a mountain 

 that was piled up. They say that the whole state of Washington, which 

 Mount Rainier dominates, was a level plain or else it was under the sea. 

 It's hard to tell what was under a mountain originally. A volcano starts 

 blowing out lava and rocks and ashes. It keeps piling up and piling up 

 and piling up some more. I don't know how long. Call it a million years. 

 Finally, Mount Rainier was built up with lava outpourings to a height 

 of almost three miles. Then the volcano quit working. Snow after snow 

 fell on the mountain as it cooled off. It packed into the crater and became 

 ice. The ice expanded and contracted, as the weather changed, cracking 

 off part of the crater. The ice flowed down the mountain side. Surely, 

 ice can flow. It isn't as solid as it looks, and it will flow when there is 

 enough pressure behind it. 



"Ever since they started flowing down the sides of Mount Rainier, 

 the glaciers have been grinding down that old mountain. They have 

 probably taken two thousand feet off the top of Mount Rainier in the 

 last million years. In another ten million years there probably won't be 

 much to look at on Mount Rainier. That's what worries the rangers. 



