OCCURRENCE OF TINGUAITE FROM KOSCIUSKO, N.S.W. 



371 



A result which agrees fairly closely with Mr. Card's calculation. 



No attempt has been made to distribute the minerals in the 

 portion soluble in HOI. Nearly the whole of the iron in the 

 original rock has apparently gone into solution, and if this is all 

 contained in the segirine as has been assumed in the above calcul- 

 ation, the aegirine must have undergone a selective decomposition, 

 as the figures do not permit of the assumption that the soluble 

 part consists of nepheline with some aBgirine. 



Mr. Card has also very kindly prepared for us the following 

 diagrams, to express graphically the molecular constitution of the 

 rock. 



A. is a Brogger diagram as modified by Hobbs, (Journ. G-eol. vin.) 



B. is a Miigge diagram (N.J.B., 1900, Vol. i ) 



