GEOLOGICAL OCCURRENCE. 



101 



bears easterly, parallel with the bedding of the quartzite. These rela- 

 tions are shown in the accompanying sketch. 



The dike is about a foot wide, and consists chiefly of coarsely crystal- 

 lized dark grayish or purplish feldspar (microcline), with grains and 

 aggregates of augite and occasional patches of quartz. The grain is quite 

 uniform, except for a thickness of about one centimeter next the walls, 

 which is of a finer grain (number 132). At one point a fragment of the 

 quartzite is inclosed in the syenite. At an apatite opening southeast of 



Figure 3.— /w/frw5/o?z of Syenite in Pyroxenite and Quartzite. 



The locality is at an apatite pit on the hill, about 30 rods southeast of the office. The front face 

 indicates the relations as shown in the wall of the pit, while the top represents the surface ex- 

 posure. 



this, in the line of strike, the syenite is seen cutting the pyroxenite, as 

 shown in relief in figure 3. The pyroxenite has been broken up, and 

 the different parts intricately involved in the intrusive mass. At this 

 exposure the different phases shown by the syenitic rock are seen grad- 

 ing into each other. In some parts the intruding rock is of a coarse 

 grained character, while in other places it shows the ellipsoidal structure, 

 grading finally into the striped gneissoid rock. At one point in the wall 

 of the pit a large mass of the pyroxenite (^, figure 3) is in contact on one 



