242 BULLETIN OF THE MUSEUM OF COMPARATIVE ZOOLOGY. 



The examination of the sections made from some of the narrow dikes 

 which cut the amygdaloid seems to show, in general, a similarity to 

 either [Q. 1'] or [6] — one series containing undecomposed augite, the 

 other none that can be identified. The great cross dike is described 

 under [Q. 8']. All of these later eruptive rocks seem in a more advanced 

 stage of decomposition than the amygdaloid. 



July, 1882. 



