24 A NATURALIST IN THE GREAT LAKES REGION 



Fig. 20. — Portion of so-called "crater" of Canon Diablo, probably made by 

 the falling of a great meteorite. 



Fig, 21. — A spiral nebula with centers of condensation, the great central one 

 giving rise to a sun, the others to planets and satellites. Photo by jMount 

 Wilson Observatory, _-. 



fiOKRrr UBRARY 



n. C. State College 



