12 N. L. Bowen — Genetic Features of 



of the analysis ' of this rock Dr. Washington noted a 

 resistance of its powder to wetting unusual in his expe- 

 rience. This resistance is characteristic of very fine 

 powders and may be connected with the ease of reduction 

 of the cracked quartz of this rock to such a fine state. 



The analysis is given in Table II under II and the cal- 

 culation of the norm, also by Dr. Washington, is given 

 with it. It proves to be that of a very unusual rock, 

 highly siliceous and showing high potash with rather high 

 lime, in which respects it resembles moldavites that are 

 believed to be of meteoric origin. 13 In its content of 

 aegiritic pyroxene it would appear to be related to the 

 alkalic rocks of the Monteregian province and thus to 

 be a cognate inclusion. The high potash would seem 

 to contradict this and the amount of silica is quite 

 unmatched in any described rocks of this petrographic 

 province. 



The other type of inclusion examined consists almost 

 exclusively of oligoclase with a little microcline. These 

 are cut by veinlets of hydronephelite. A little mica and 

 a greenish pyroxene are the only other constituents. 



This is apparently a rock of the alkalic series also, and 

 possibly all of the inclusions examined are to be regarded 

 as cognate or belonging genetically with the containing 

 rock. 



Relations of the Minerals. 



We shall now return to a discussion of the relations of 

 one mineral to another in the principal type or, better 

 perhaps, in the mass as a whole. 



In order that the details may be more intelligently fol- 

 lowed, the conclusion arrived at from them will be 

 anticipated and may be stated as follows. The mass 

 originally consisted of chrysolite and augite, nearly com- 

 pletely consolidated as such. It was then acted upon 

 with falling temperature by an alkalic liquid (magma) 

 which was, in part at least, its own interstitial liquid, and 

 as a result of this action the other minerals, biotite, mon- 

 ticellite, melilite, perovskite, apatite and marialite were 

 formed. The minerals may therefore be divided into two 

 classes, the original minerals augite and chrysolite and 



13 U. S. Geol. Survey, Prof. Paper 99, p. 53. 



