TRACHYTE ON THE ISLAND OF HAWAII 523 



according to the Quantitative System, bring out many similar signifi- 

 cant facts, to be tal<:en into account in this discussion. They show 

 the essential identity of many magmas having widely different asso- 

 ciations, and indicate that the designation of a given rock or magma 

 as belonging in the train (Gefolgschaft) of certain parent magmas 

 can at most be true only of certain peculiar or aberrent modifications, 

 as a complete statement available for systematic classification. 



Whitman Cross. 



