J. A. Dresser — A Rare Rock Type. 73 



Norm 



Anorthite ___ 12*23 



Albite 2*88 



Nepheline 2*13 



Orthoclase 2*22, total salic 19*46 



Diopside 47*24 



Olivine 25*05 



Magnetite , 3 *48 



Ilmenite .-. 2*89, total femic 78*66 



C0 2 , calcite being secondary *62 

 HO... *88 



99*62 



The rock thus falls in — 



Class IV Dof emane 



Order I Hungarare 



Section 2 (name proposed) Quebeciare 



Rangl " " . Quebecase 



Section 2 " " Bruniase 



Subrang 2 Palisadose 



The new names used above are proposed on the advice of 

 Professor J. P. Icldings and Dr. F. D. Adams, to both of whom 

 the writer is indebted for advice in the matter. 



A rock of closely similar composition has recently been 

 described by Professor J. Yolney Lewis* from the Palisades 

 of the Hudson. This is a highly olivinitic facies of the diabase 

 of that well-known locality. An analysis of it is given in 

 column IV. From it the name Palisadose has been given to 

 the subrang of. the Quantitative Classification, of which it was 

 the first representative rock described. 



As the rock from St. Bruno is a distinct phase of the well- 

 defined petrographic province of the Monteregian hills in 

 which allied varieties are likely to be found, it has been 

 thought that the larger divisions of the Quantitative Classifi- 

 cation might be suitably named as above proposed. 



The nearest related rock in the Monteregian series, that has 

 thus far been described, is that named Yamaskite by Dr. G. 

 A. Young from Yamaska Mountainf in which it occurs. The 

 analysis of this rock is given in column II, while in column 

 III is given an analysis of Belcherose from Belchertown, Mass., 

 described by Professor B. K. Emerson (U. S. G. S. Mono- 

 graph XXIX, p. 347, 1898). 



McGill University, Montreal, Canada. 



* Annual Eeport of the State Geologist of New Jersey for 1907, p. 124. 

 f Report Geological Survey, Canada, vol. xvi. 



