THE MONTEREGIAN HILLS 



267 



Albite 



Anorthite 



Orthoclase 



Nepheline 



Diopside . 



Olivine . . 



Magnetite 

 Ilmenite . 

 Apatite . . 

 Water 



34CaO. SiOg 

 7FeO. SiOg 



jyMgO. SiOg 

 6FeO. iSiOg 



JSMgO.iSiO, 



35-63 

 23.07 

 II . 12 



- 3 • 94 ) 



- -92 [ 



- 2.70 1 



- .6i( 



- I. 61 s 



69.82 



5-40 

 7-56 



2.22 



6.26 



4.71 



2.68 



.68 



99-33 



No. 



( 53 CaO. SiOg 

 - 18 FeO. SiOg 

 (35 MgO. SiO, 

 \ 21 FeO. 1 SiO., 

 UsMgO.i-SiOs 



28.62 

 14.23 

 15-05 



- 6.15 

 -2.38 

 -3-50 



- 2.14 / 



- 2 . 94 ^" 



BaO = . 08, Excess FeO = .07 



57-90 

 11.83 

 12.03 



5-08 



4.41 



5-01 



2-59 



-95 



-15 



99-95 



No. I thus takes the following position in the classification in 

 question : 



Class II, dosalane. 



Order 5, germanare. 



Rang 3, andase. 



Subrang 4, andose (grad = polmitic). 



Its precise designation would be nepheliiie-bearing grano-andose 

 or in some cases nepheline -bearing tracho-a?idose. 



No. 2, however, belongs to the next order and is domalkalic. 

 Its position is as follows : 



Class II, dosalane. 



Order 6, norgare. 



Rang 2, essexase. 



Subrang 4, essexose (grad = prepolic). 



It would therefore be termed a nepJieline-bearijig grano-essexose . 

 It is therefore seen that the essexite from the central portion of 

 Mount Johnson (No. 2) is practically identical in character and 

 composition with the essexite of the original locality at Salem, 

 Mass. (Analysis IV), while the outer andose is poorer in nephe- 

 line and has a somewhat larger proportion of lime as compared 

 with the alkalies. 



The proportions of the several minerals present in thin sec- 

 tions of the specimens analyzed were then determined by the 

 system of diametral measurements proposed by Rosiwal.' In 



^ Verhd. K. K. Geol. Reichsansi. (Wien, 1898), p. 143. 



