548 STUDIES FOR STUDENTS 



EXPLANATION OF PLATE III 



The figures in this plate illustrate the results of crushing samples 

 of the strongest limestone of Wisconsin. The sample in the lower 

 right hand corner, Fig. 6, gave a crushing strength test of 42,787 

 pounds per square inch, which is thought to be the highest record 

 obtained for any limestone, dolomite, or marble quarried in the United 

 States. This sample shows, near the apex of the somewhat irregular 

 cone, the concentric cleavage structure, which is typically developed in 

 the arranite. 



