WASHINGTON: italite; 



271 



closely followed by some Italian leucite trachytes and tephrites. 

 The noselite, whose presence is indicated by the SO3 and high 

 CaO, probably forms part of the glass, as does melilite, the pres- 

 ence of which is also indicated by the norm. 



In the quantitative classification the position of the rock is 

 shown by the symbol I.9.1.1, and the new perpotassic subrang 

 is called monfinose. No rock at all analogous to this is repre- 

 sented in the usual or modal classifications and, though the name 

 "leucitite" might logically be applied to it, implying a rock com- 

 posed essentially of leucite, as suggested by Cross many years 

 ago, this name cannot be used, because of its present connotation 

 and the inadvisability of redefining old names. The new name 

 given the rock is italite, after the country in which it occurs, and 

 which is so famous for its abundance in leucitic lavas. 



A partial analysis (made on 0.0639 gram) of the garnet showed 

 that it is a highly titaniferous melanite, analogous to schorlomite. 

 Its refractive index, n = 1.94, is remarkably high, in which it 

 resembles other titaniferous garnets, whose refractive indexes 

 have also been recently determined by Merwin. 



TABLE I 

 Analysis op Italite 



Si02 51 02 



AI2O3 22.21 



Fe203 1 . 48 



FeO 0.57 



MgO 0.14 



CaO 2.31 



NasO 1.67 



K2O 17 -94 



H2O + 0.82 



H2O- O.II 



CO2 None 



TiOa 0.57 



Zr02 o . 06 



P2O5 o . 02 



SO3 0.76 



CI 0,08 



(Ce,Y)203 Trace 



MnO 0.01 



BaO 0.20 



99-97 



Supplementary Note. — While the above was in press I have 

 studied another similar, remarkable leucite rock, that forms an 

 "ejected block" at Monte Somma. It is much like the italite 



