628 JOE. VOGEL 
A few quite small individuals of magnetite or ilmenite also 
appear in the olivine. 
The sequence of crystallization cannot here be explained in 
detail, but so much can be said, that the olivine commenced crys- 
tallizing at a very early stage, and certainly not much magnetite 
Fic. 27.—Photomicrograph (25:1) of “titanomagnetite’’-olivinite from Cum- 
berland, Rhode Island. White=olivine, black =“‘titanomagnetite.”’ 
or ilmenite can have been solidified before the commencement of 
crystallization of the olivine. 
Very interesting in structural respect is a “‘titanomagnetite’’- 
olivinite (Fig. 28) from Fiskaa in Séndmére, Norway, consisting 
of about 50 per cent olivine (according to optical investigations 
0.35-0.4 Fe,SiO,:0.65-0.6 Mg,SiO,); about 40 per cent magne- 
tite plus ilmenite, about 5 per cent spinel; and in addition locally a 
little hypersthene. 
The olivine, with no sign of an idiomorphic contour, shows in 
nearly every individual an intimate intergrowth with the iron ore, 
