Oeology of the Region About DeviVs Lake. 125 



sandstone consists of small rounded gi*ains of quartz, and is 

 very loosely cemented. It can easily be crumbled with the 

 fingers. Hand pieces of the quartzite may be obtained in all 

 stages from tMs friable sandstone to that wbere the grains are 

 apparent and the rock is less friable, to that where the homo- 

 geneousness is here nearly approached but the small grains 

 can still be seen, and finally to the perfect homogeneous 

 quartz. No sharp geographical line of demarcation between 

 the sandstone and quartzite, and no gradation in any direction 

 was observed. 



The homogeneousness of the colored quartzite is not as per- 

 fect as it appears. Whenever a surface has been subjected to 

 the weather, the small grains come to view again. 



The bandings of the quartzite are yqvj similar to those in 

 the undisturbed sandstone. These bands sometimes consist of 

 layers of fine grains of sand. 



Some of the great blocks of quartzite, which have fallen 

 down the sides of the valley are most beautifully covered with 

 regular ripple marks. They must have been first made in the 

 moving sands. 



The layers are nearly as perfect as in the sandstone, and 

 have a dip equal to the inclination of the ridges. The dip on 

 either side can be seen best from the opposite side. The anti- 

 clinal ridge on the east side of the lake is removed by the 

 valley, which trends to the east, and on the west by another 

 valley, which comes down to the lake. Vertical joints also 

 lead to the conclusion that the ridge has been formed by the 

 upheaval of the horizontal layers of sandstone. The layers 

 were not traced north and south to determine whether they 

 are continuous horizontally. 



How WAS THE Sandstone Changed ? — Both the nature of 

 the rock and its position forbid the idea of aqueous fusion or 

 active volcanic agency. The change must have taken place by 

 the purely wet way of partial solution and crystallization, or 



