6i8 



HENRY S. WASHINGTON 



Ijolite. — The analysis of this type, from below Dr. Thornton's, 

 has been already published,' but is here repeated, with the addi- 

 tion of several constituents which have been determined since. 

 In II is given the analysis of a typical ijolite from liwaara, in 

 Finland. The two do not differ materially, except that I is 

 higher in CaO and correspondingly lower in NagO. 



I. Ijolite, Magnet Cove. Washington, analyst. Bull. Geol. Soc. Ar?i., Vol. XI, p. 



399, 1900. Sp. Gr. 3084 — 26''C. 

 II. Ijolite, liwaara, Finland. Sahlbom, analyst. V. Hackman, Bull. Com. GeoL 

 Finl., No. II, p. 17, 1900. 



The mineralogical composition of the two is given below, 

 that of Ila being Hackman's calculation. II is almost exactly 

 half nephelite, while I contains rather less than half of this 

 mineral, but both may reasonably be called mesocratic. Hack- 

 man's specimen did not contain any garnet, but this is a very 



' H. S. Washington, op. cit., p. 399. 



^ There is a clerical error in Hackman's results, as he gives the nephelite as 

 51.02, the sum as 100.50. 



