1*74 Canadian Record oj Science. 



at the other end of the series, in which the pyroxene largely 

 predominates and the plagioclase occurs only in very small 

 quantity, or that of troctolite in which the plagioclase and 

 olivine greatly predominate and the pyroxene is absent as 

 an essential constituent. 



They constitute a well denned type which both on account 

 of its widespread occurrence and its constant character oc- 

 cupies an independent position in the classification and can- 

 not suitably be included anywhere else. 



These anorthosites were found by the older geologists of 

 Canada in parts of the Laurentian widely separatad from 

 one another, sometimes occurring in small areas and again 

 occupying large districts. Later investigations have made 

 known the existence of many additional areas, great and 

 small. The literature of the subject is extensive, the biblio- 

 graphy comprises about a hundred titles, but these com- 

 munications are for the most part short and do not enter 

 into descriptive details. 



This anorthosite has been recognized at the following 

 localities : To begin at the Atlantic coast (see large map), 

 one area is known (and as far as can be ascertained from 

 observations by travellers several probably occur) on the 

 east coast of Labrador. From this the original labradorite 

 was obtained, as well as the specimens of hypersthene 

 which have found their way into mineralogical collec- 

 tions the world over. Another locality is on the south- 

 west end of the island of Newfoundland. Farther to 

 the west, on the north shore of the St. Lawrence, Bay- 

 field mentions the occurrence of labradorite and hypers- 

 thene on a point 15 miles east of the island of Ste. 

 Genevievre, or about 50 miles east of the Mingan Islands. 1 

 Selwyn 2 found the rock on the same coast at Sheldrake, 

 between the Mingan Islands and the Moisie River, and 

 mentions the occurrence at this place of beautiful opal- 



1 Bayfield, Notes on the geology of the north coast of the St. Lawrence. Trans. 

 Geol. Soc. London, 2 Ser. Vol. V. 1833. 



2 Selwyn, Summary Report of the operations of the Geological and Natural 

 History Survey of Canada 1889, p. 4. 





