GEOLOGY AND SCENERY OF NORTHEAST COAST 91 



were unquestionably the conditions under which the old 

 Archean chain of Labrador was upheaved. 



As we have seen, enormous lateral pressure, pressure too 

 great to be comprehended by the human mind, ridged up 

 the rocks to alpine heights. During that process much of 

 the crystallization and recrystallization of the Archean 

 rocks took place. It was, therefore, natural that the min- 

 erals of the rocks should be arranged with reference to the 

 pressure. They might be expected to lie in the rock with 

 their longer axes perpendicular to the lines of force, assum- 

 ing thus the position offering greatest resistance to that 

 force. This is the case for probably much the largest area 

 of rock in the coastal belt. Many granites and allied rocks 

 which had been " intruded," in the molten state, into the 

 base of the range, were squeezed by the continued appli- 

 cation of the same mountain-building forces, and their 

 minerals, too, have been crushed and driven into alignment 

 at right angles to the direction of pressure. So it has come 

 about that the commonest rocks found on the coast are 

 what are called " crystalline schists": gneisses, which are 

 like granite in composition but show on the broken surface 

 the parallelism of the minerals ; mica schists, with the same 

 (schistose) structure, yet lacking the white or pink feldspar 

 crystals of gneiss ; hornblende schists, in which the familiar 

 mica is replaced by the less familiar but likewise important 

 mineral, hornblende; and a large number of other rock- 

 species of similar structure. 



The nature of the original material from which the crys- 

 talline schists have been made, that is, the composition 

 of the earth's crust in a mountainous region before the moun- 

 tain-building began, is one of the most interesting problems 



