Geol. Mag., 1917. 



Plate XIII. 



Fig. 1. 



Fig. 2. 



J 



■<:i^ 



Fig. 3. 



Fig. 5. 



Fig. 6. 



n 



' A 



Fig. 7. 



//. L. H. del. Fig. 8. 



SURFACE FEATURES OF DISCOIDES AND CONULUS. 



