﻿806 Canadian Record of Science. 



Manouan Branch of the Periboiika and on the lower part 

 of the Ungava lliver, in the Labrador peninsula ; 

 while similar rocks, which would seem to belong to this 

 series, but which have not as yet been thoroughly 

 examined, have been met with about southern Baffin's 

 Land, and possibly about Baker Lake near the head 

 of Chesterfield Inlet, as well as on the west coast of 

 Hudson Bay and also at Cross Lake on the Nelson Eiver. 

 The Fundamental Gneiss consists of various igneous 

 rocks closely allied in petrographical character to granites, 

 diorites and gabbros, and which almost invariably have a 

 more or less distinct foliation. Where this foliation is 

 scarcely perceptible it becomes very difficult to decide 

 whether the rock is an intrusive granite or diorite, or 

 a very massive form of the gneiss in question. The 

 different varieties of gneissic rock alternate with or 

 succeed one another across the strike, or sometimes cut 

 one another off, suggesting a complicated intrusion of one 

 mass through the other, but there is usually a general 

 direction of strike. to which, in any particular district, the 

 foliation of all the varieties conform. The associated 

 basic rocks are very dark or black in color and are usually 

 foliated, but sometimes this foliation is absent and the 

 rock occurs in masses of all sizes and shapes scattered 

 through the acid gneisses, and in the great majority of 

 cases so intimately associated with the latter that it is 

 impossible to separate the two in mapping. The smaller 

 of these masses can be distinctly seen to have been torn 

 from the larger, which latter are often of enormous size. 

 This process can be observed in all its stages. The 

 granitic gneiss invades the great basic masses, sending off 

 wedge-like arms into them, which tear them apart and 

 anastomose through them in the most complicated manner. 

 These smaller masses can then be observed to be separated 

 into still smaller fragments, which either from the fact 

 that they split most readily in the direction of their 



