286 HENRY S. WASHINGTON 



I. Camptonite (?). Salem Neck. H. S. Washington anal. 



II. " Diorite-Porphyrite." St. Johns, N. B. W. D. Matthew, Trans. N. Y. Acad. 

 Sci., Vol. XIV, p. 213, 1895. 



III. Camptonite. Portland, Me. E. C. E. Lord, Amer. Geol., Vol. XXII, p. 

 344, 1898. 



IV. Bronzite-Kersantite. Hovland, Norway. Brogger, op. cit, Vol. Ill, p. 75. 



An analysis of a fresh specimen from a narrow dike cutting 

 foyaite on Salem Neck is given in I. The low titanium oxide 

 accords with the absence of titanite and the character of the 

 pyroxene. It is evident that alumina largely replaces ferric 

 oxide in the ferro-magnesian minerals. This is a feature of 

 barkevikite as shown by Flink's analysis, 1 and some of the horn- 

 blendes whose composition has been calculated by Brogger, 2 as 

 well as of the hornblende of Hawes's camptonite. 3 



As was stated above very similar rocks have been observed 

 in New England. For instance, it resembles a specimen from 

 Livermore Falls, near Campton, N. H., for which I am indebted 

 to Professor Pirsson. This, however, does not carry hornblende 

 phenocrysts, and is also like some of the camptonites of Lake 

 Champlain. 4 Hobbs 5 also describes similar rocks as augite- 

 diorite, occurring in connection with the diabase of Medford, 

 Mass. A nearly identical rock is described by W. D. Matthew 6 

 as occurring in dikes near St. Johns, N. B. The hornblende is 

 also apparently barkevikite, and an analysis of this rock is given 

 in II. Very recently E. C. E. Lord 7 has described a dike of 

 camptonite from Portland, Me., which is closely allied, and the 

 analysis of which is given in III. These two contain consider- 

 ably more alkalies than those described in this paper. These 



1 Dana, A System of Mineralogy, New York, 1892, p. 403. 



2 Brogger, op. cit., Ill, p. 110. 



3 Lord, Amer. Geol., Vol. XXII, p. 343, 1898; also, Rosenbusch, Elem. Gest- 

 lehre, p. 234, No. 1, 1898. 



4 Kemp and Marsters, Bull. U. S. G. S., No. 107, p. -29, 1893. 



s W. H. Hobbs, Bull. Mus. Comp. Z06L, Vol. XVI, p. 10, 1888. 



6 W. D. Matthew, Trans. N. Y. Acad. Sci., Vol. XIV, p. 210, 1895. 



7 E. C. E. Lord, Amer. Geol., Vol. XXII, p. 342, 1898. Cf. Kemp, dikes near 

 Kennebunkport, Me., Amer. Geol., p. 129, 1890. 



