TITLES AND ABSTKACTS OF PAPERS 155 



belief that this interpretation of the origin of anorthosites is substantially 

 correct. A conception of the Adirondack anorthosite-syenite complex as essen- 

 tially a stratified mass, with syenite above and anorthosite below, together 

 with the evidence favoring this conception, were ofCered for consideration. 



Presented in abstract extemporaneously. 



Discussion 



Dr. F. D. Adams : Doctor Bowen has asked those members who have studied 

 anorthosites in the field for information on two points : First, Do anorthosites 

 occur in small dikes? and, second, Do these rocks commonly display protoclastic 

 structure? Having examined a number of the anorthosite areas of the Cana- 

 dian shield, I may say that I cannot remember any occurrence of anorthosite 

 in a form of a small dike, while on the other hand protoclastic structure is 

 widespread in many, if not all, of the areas in question. 



Mr. J. A. Dressee : Bordering the great anorthosite area of the Saguenay 

 district on the south, there is a large development of syenite in the vicinity of 

 the Saguenay River. The detailed relations have not been worked out, but the 

 field evidence, as far as known, suggests strongly that on approaching the 

 anorthosite the syenite grades into a granite which is plainly intrusive into the 

 anorthosite. 



Further remarks were made by. Professors Gushing and Graton. 



CLASSIFICATION OF METAMORPHIC ROCKS 

 BY WILLIAM J. MILLER 



{Abstract) 



A comprehensive classification of metamorphic rocks was presented, the 

 main principles of which are based on origin and structure, and these prin- 

 ciples were discussed. The attempt has been made to work out a satisfactory 

 classification without the introduction of new terms. 



Presented in abstract extemporaneously. Discussion put into exhibi- 

 tion room for 4 o'clock. 



RELATIONSHIP BETWEEN THE IGNEOUS AND METAMORPHIC ROCKS OF THE 

 DISTRICT OF COLUMBIA AND VICINITY 



BY C. N. FENNER 



(Abstract) 



The rocks of this region consist of a series of chloritic, sericitic, and micace- 

 ous schists and gneisses (grouped by the U. S. Geological Survey as Carolina 

 gneisses), associated with bodies of massive to gneissoid igneous rock, generally 

 of the composition of diorite or granite. Many of the bodies of undoubtedly 

 igneous character show an abundance of inclusions of foreign material, and 



1 Introduced bj' C. N, Fenner. 



