and their Contact Zones. 65 



the dip and strike of the schists. The character of this 

 aplite is that already described in the last section. The 

 total thickness of these bands is about 120 feet. 



e. A schistose rock, similar to that described at c. A 

 thin slice prepared from a sample taken from this place 

 showed it to be a fine-grained foliated rock. The ground 

 mass is composed of minute plates of mica, which is either 

 colourless or faintly brown. In this mass are small grains of 

 quartz and flakes of brown magnesia mica. The plates of 

 colourless mica which form the ground mass of this rock 

 are, as compared to those of c, much smaller in dimensions, 

 and consequently, the mass being the same, more numerous. 

 As before, there is a considerable amount of amorphous, 

 opaque, black material, and minute black or dark brown 

 flakes. Microliths are of minute size and undeterminable 

 character • some, however, suggest minute specks of chlorite. 



/. The schists at this point have in the distance from 

 e (about eleven chains) changed their character. They are 

 no longer micaceous, and are less schistose and more 

 indurated. Samples collected from this place I prepared as 

 thin slices taken parallel to and across the planes of deposit, so 

 far as they were ascertainable from the crumpled and con- 

 torted condition of the rock. The former show by ordinary 

 light a colourless ground mass which, in the thinnest edges of 

 the slice, suggests overlapping, minute plates. In this are 

 vast numbers of minute bent and contorted, pale greenish 

 fibres, which, when lying perpendicular to the slice, are seen 

 as dots. These fibres are often arranged parallel to each 

 other, or surround the grains and lenticular masses of 

 quartz which lie in the ground mass. The dimensions of 

 these fibres are too minute to afford satisfactory observations 

 as to their being or not being dichroic ; but so far as I could 

 ascertain, they are. These observations suggest chlorite. 

 The slice prepared perpendicular to the bedding showed the 

 rock arranged in simulated foliations, the alternations being 

 a ground mass, such as I have just described, in which the 

 chlorite fibres are very numerous, and arranged in a direc- 

 tion parallel to the bedding, and a ground mass in which the 

 chlorite fibres are very rare. v Between and in these alter- 

 nations are grains and lenticular masses of quartz. Through- 

 out the mass there are minute black particles which are not 

 affected by hydrochloric acid. 



g. Here the rocks have assumed the appearance of 

 indurated sediments, alternating somewhat in texture, and 



