WOLFF : LEUCITE-TINGUAITE FROM BEEMERVILLE, N. J. 277 



other combination with ferric iron than as aegirine ; the present case 

 indicates some combination with ferrous iron as yet unknown, and of 

 course purely hypothetical. 



A rough quantitative mineral calculation of the rock gives : 



Pyroxene, 22 per cent. 

 Nepheline, 36 per cent. 

 Orthoclase, 38 per cent. 

 Titanite, Apatite, etc., 4 per cent. ; 



the analcite actually present is excluded but would of course lower the 

 percent of nepheline. Analyses D and E are introduced as the only 

 published ones of the elaeolite syenite of Beemerville ; the incomplete 

 analysis E shows much similarity with the tinguaite. Analyses F and 

 G of leucite-tinguaites differ mineralogically from the Beemerville tin- 

 guaite by containing sodalite. 



It should be mentioned that J. F. Kemp {loc. cit.) has described two 

 camptonitic dikes — six, and nine and a half miles respectively distant 

 from the Beemerville dike — in which certain curious spheroids without 

 definite crystal outlines and composed mainly of analcite are referred to 

 original leucite, of which some traces are stated to remain. 



Mineralogical Laboratory, 



Harvard University, Jan., 1902. 



