36 THE CANADIAN NATURALIST. [March 



The uame of norite, in allusion to Norway, was given by 

 Esmark to a rock composed chiefly of labradorite, which is found 

 in several localities in that country.* I had already remarked 

 the close resemblance between two specimens of norite obtained 

 from Krantz of Berlin, and the labradorite rocks of North America 

 just noticed, when, in 1867, I had the opportunity of examining, 

 at the Universal Exhibition at Paris, a collection of Norwegian 

 rocks selected for ornamental purposes, exhibited by the Royal 

 University of Christ iania. Prominent among these was a series 

 of the norites, which could not be distinguished from the 

 labradorite rocks of the Upper Laurentian or Labrador series of 

 this continent. In a printed note, accompanying this collection 

 from the University, it is said that the numerous varieties of rocks 

 consisting of labradorite with hypersthene, diallage and bronzite, 

 have been, in the geological map of Southern Norway published 

 at Christiania in 1866, designated by the common name of gabbro. 

 This note at the same time suggests that the "name of norite 

 should be preserved for certain varieties of gabbro rich in 

 labradorite, which varieties may in great part with justice be called 

 labradorite rock, since labrador feldspar is their predominent 

 element." With this excellent suggestion I heartily concur, 

 remarking, however, that the name of gabbro. as an ill-defined 

 synonym for certain anorthosite rocks, including in part diorite, 

 diabase, hyperite, and even confounded with the non-feldspathic 

 rock, euphotide, may very well be dispensed with in lithology. 



By referring to the geological map just mentioned, it will be 

 seen that these so-called gabbros occupy considerable areas in the 

 Laurentian gneiss region of Norway. By the authors of the 

 map, Messrs. Kjerulf and Dahl, tiie gabbros are regarded as 

 eruptive, though they are described at the same time as often 

 assuming the character of stratified rocks. It should, however, 

 be noticed that the geologists go so far as to regard the whole of 

 the granitic gneiss of the region as unstratified and of plutonic 

 origin. 



The specimens of these norites exhibited in Paris were in 

 blocks, polished on one side^ and as was observed in the note 

 accompanying them, presented a curious resemblance to certain 

 varieties of marble. It is worthy of remark that Emmons, in his 

 report on the Geology of the Northern District of New York, 



"* See, farther, Zirkel, Petrographie III., 131. 



