120 HENRY S. WASHINGTON 



prismatic crystals of aegirite with fewer small flakes of brown 

 biotite, are strewn in a colorless base composed of small tabular 

 alkali-feldspars with interstitial nepheline. Colorless needles of 

 what is probably diopside are also present, but no magnetite was 

 seen. The rock shows a well marked flow structure. 



Of these rocks we have two analyses, both already published, 

 one of the Pickard's Point analcite-tinguaite, the other of the 

 biotite-tinguaite. With them are given for comparison analyses 

 of the border and center of the Hedrum tinguaite dike and the 

 Kjose-Aklungen solvsbergite. 



99.92 100.04 99.83 99.21 100.33 99-74 



I. Analcite-Tinguaite, Pickard's Point. H. S. Washington anal. Trace of S0 3 . 

 Am. Jour. Sci. (4), VI, p. 185, 1898. 



II. Biotite-Tinguaite, Gales Point. A. S. Eakle anal. Am. Jour. Sci. (4), VI, 

 p. 491, 1898. 



III. Tinguaite (dike border). Hedrum, Norway. G. Pajkull anal. Brogger, 

 op. cit., I, p. 113. 



IV. Tinguaite (dike center). Hedrum, V. Schmelck anal. Brogger, op. cit., 

 p. 191. 



V. Nepheline-Solvsbergite. Kjose Aklungen, Norway. V. Schmelck anal. 

 Trace of P s 5 . Brogger, op. cit., p. 102. ,- 



VI. "Phonolite" (Tinguaite?) H. N. Stokes anal. Southboro, Mass. Bull. 148. 

 U. S. G. S., p. 77. 



In I the only points which need be mentioned here are 

 the rather low silica, high soda, and, for so fresh a rock, the high 



