Nature's Notes * * * * * 103 



find a forest. The forest may be covered with volcanic mud or ash. 

 Then more sandstone ; thea gravel, the deposit of a river. In one part 

 of the park they know of twelve forests, buried one on top of the other, 

 volcanic mud deposits between them. Eons passed while these forests 

 were growing, each above the tallest tops of its predecessors. 



In Yellowstone are found several of these petrified forest areas. 

 Lava and ashes destroyed the trees, mud covered them up and provided 

 silica, which replaced the wood cells, preserving for all time the grain of 

 the wood. The preservation of the rings of these ancient trees is of the 

 greatest importance in piecing together the story of the earth. For a 

 long time scientists thought that a large, fat ring indicated a moist, warm 

 year, and that a thin ring indicated a year of drought. It is definitely 

 established that these rings do contain the secrets of climatic records in 

 prehistoric years. In the great redwoods of Sequoia and Yosemite 

 parks, some of which have fallen in recent years, naturalists have traced 

 by means of rings the weather records for the past three or four thou 

 sand years. Now if they can connect the record of the rings of the 

 sequoias in their ancient youth with that of the petrified big trees in 

 other parks and monuments, it may be possible to trace the weather re 

 port back to the time of the Garden of Eden, or beyond. 



Nature leaves her notes in unexpected places ! 



The Carnegie Institution, under that great scientist, teacher, and 

 executive, Dr. John C. Merriam, is conducting extremely interesting in 

 vestigations of tree rings. Dr. Ellsworth Huntington has traced back 

 climatic conditions for thousands of years already. Other scientists, 

 working with archaeologists and ethnologists, have studied tree rings in 

 wood found in cliff dwellings and other prehistoric structures and have 

 traced human migrations, age of buildings, progress of forgotten people, 

 and other important data. 



From the study of the record kept in recent years of the rate of 

 deposit of limestone on the cone of Old Faithful, it has been discovered 

 that it took the geyser at least forty thousand years to build up its cone. 

 Some of the other geysers took much longer. Castle Geyser is estimated 

 to be 250,000 years old. Liberty Cap, that queer -cone near Mammoth 

 Hot Springs, took ages to build. No one knows how long it has been 

 extinct, yet for centuries nothing has toppled it over. For all the heat 

 and the weird activity below the earth, the surface has been at rest for 

 many, many years. 



Yet it is recorded in the diaries of early hunters and trappers of the 

 Rockies that a volcano was seen to spout brimstone and fire in the Yel 

 lowstone area as late as 1811. Unfortunately these early woodsmen kept 

 poor records and the rangers cannot now identify the peak the pioneers 

 saw erupting. Equally unfortunate is the fact that many of these early 



