THE WEDGE-WORK OF ROOTS 



479 



Iowa it was not until recently that the writer's attention was called 

 to a tree-split boulder in our state. Mr. Harold Corey, a member of 

 the writer's physiography class at the University a few years ago, 

 produced a photograph which he had taken of such a boulder which 

 he modestly contended was as good an example as his textbook illus- 



FiG. 120. — A granite boulder at Nashua, Iowa, which has been split in two by 

 an elm tree growing from a crevice in the stone. Photo by Harold Corey. 



tration "taken," as he said, "from some other state." Mr. Corey's 

 boulder is located within the corporate limits of the town of Nashua 

 in Chickasaw county. It is situated in a cultivated field on the 

 Greeley estate in the northwest part of the town about one-fourth 

 mile west of '-the Catholic church. The field is in the southwest 

 quarter of section 18, township 94 north, range 14 west. 



The stone is a coarse-grained feldspathic granite, somewhat de- 

 cayed and of the type that is very common on the surface in Chick- 

 asaw and Floyd counties. It measures approximately 11x17x5 feet 

 above the ground. The cleft divides the stone into two unequal 



