172 BULLETIN OF THE MUSEUM OF COMPAKATIVE ZOOLOGY. 



The occurrence of this keratophyre as a surface flow in close prox- 

 imity to the large intrusive masses of elfeolite- sodalite- zircou-syenite 

 of Salem Neck and the islands in Salem Harbor, and the augite- zircon- 

 syenite of Marblehead and the Beverly shore, is interesting, as showing 

 the various forms assumed here by the alkaline magmas under different 

 geological conditions or at diflerent periods. 



June, 1S90. 



