F. D. Adams — New JVepheline Rock. 275 



Si0 2 __ _- 39-74 



Ti0 2 -13 



A1 2 3 _ 30-59 



Fe 2 O s ._. -44 



FeO 2-19 



MnO _ r -03 



CaO __ _ '__. 5-75 



MgO -60 



K 2 3-88 



Na 2 . _ 13-25 



C0 2 2-17 



S0 3 ._ trace 



CI -02 



S._ ..- -07 



H 2 1-00 



99-86 

 If, following the methods of the Quantitative Classification, 

 the Norm of the rock be calculated, that is to say the propor- 

 tion of standard minerals which would give a magma of this 

 composition, or in the form of which the rock under other con- 

 ditions of cooling might have solidified, this is found to be as 

 follows : 



Anorthite 12-51 



Nepheline _ 67'72 



Leucite ._ 8-28 



Olivine . _ 3'70 



Akermanite -40 



Magnetite '70 



Ilmenite .. '30 



Pyrite . . "14 



Calcite - 4-92 



98-67 

 Water 1-00 



99-67 

 This gives the rock the following position in the Quantitative 

 Classification : 



Class 1 — Persalane. 



Order 8 — Ontarare. 



Rang 2 — (Domalkalic). 



Sub-rang 4 — (Dosodic). 



As this is the first Ontarare which has been described, the 

 rangs and sub-rangs have received no names as yet. It is pro- 

 posed, therefore, to call rang 2, Monmouthase, and sub-rang 4, 

 Monmouthose, from the township of Monmouth in which this 

 rock is found, while, as an ordinary designation, the name 

 Monmouthite may be applied. 



