Bulletin, Dcnison University. Vol. XII, Art. XI. 



PLATE Xlll. 



Fig I - View sho^vin^ ihe .potted appearance of the rock ._in a surface broken 

 at right angles to the longer direction of the pencils. Photographed from a hand 

 specimen. (One-half natural size.) 



Fig. 2.— View showing approximately parallel black streaks and pencils on rock 

 surface broken parallel to the direction of the pencils. Photographed from hand 

 specimen. (One-half natural size.) 



