52 Field Columbian Museum — Geology, Vol. III. 



sphere. This number is of a very convenient magnitude, varying 

 from i to 16.4 for the forms in the collections. This modulus is the 

 reciprocal of the coefficient of rotundity. 



Table of Specific Gravity and Modulus of Rotundity of Clay- 

 stones. 



Locality. Mus. No. 



G 

 Riga, Vermont. - 41-1 



39-i 

 66-2 



39-2 



4i-3 



72-3 



" 72-1 



69 

 72-2 



39-3 

 37-3 

 38-i 

 3 7-4 

 69-4 

 40-1 

 40-2 

 69-2 

 38-2 

 40-2 



69-3 

 37-2 



37-i 

 Connecticut River. 805-6 



805-8 



76-2 



■ " 752-2 



805-7 



70-2 



" . . 70-1 



55-2 



75-i 

 805-2 



805-4 

 805-5 



