432 Canadian Record of Science. 



the deformation is carried on slowly the resulting rock 

 is stronger than when the deformation is rapid. 



Thin sections of the deformed marble, passing 

 vertically through the unaltered cone and the 

 deformed portion of the rock, were readily made, and 

 when examined under the microscope clearly showed 

 the nature of the movement which had taken place. 

 The deformed portion of the rock can be at once 

 distinguished by its turbid appearance, differing in a 

 marked manner from the clear transparent mosaic of 

 the unaltered cone. This turbid appearance is most 

 marked along a series of reticulating lines running 

 through the sections, which, when highly magnified, 

 are seen to consist of lines or bands of minute calcite 

 granules. They are lines along which shearing has 

 taken place. The calcite individuals along these 

 lines have broken down, and the fragments so pro- 

 duced have moved over and past one another, and 

 remain as a compact mass after the movement ceased. 

 In this granulated material are enclosed great 

 numbers of irregular fragments and shreds of calcite 

 crystals, bent and twisted, which have been carried 

 along in the moving mass of granulated calcite as the 

 shearing progressed. This structure is therefore 

 cataclastic, and is identical with that seen in the 

 felspars of many gneisses. 



Between these lines of granulated material the 

 marble shows movements of another sort. Most of 

 the calcite individuals in these positions can be seen 

 to have been squeezed against one another and in 

 xiiany cases a distinct flattening of the grains has 

 resulted, with marked strain shadows, indicating that 

 they have been bent or t^\usted. They show, more- 

 over, a finely fibrous structure in most cases, which, 



