100 C. H. CxORDON — SYENITE-GNEISS (lEOPARD ROCK) FROM CANADA. 



venieiice may be treated separately, though they belong to the same rock 

 mass and grade into eacli other almost imperceptibly. They are — 



Coarse grained syenite-gneiss. 

 Ellipsoidal syenite-gneiss (leopard rock). 

 Streaked s^^enite-gneiss. 



Geological Occurrence of the Rock. 



The rock here described occurs in the form of dikes, sometimes cutting 

 across the strike of the inclosing rocks and sometimes intercalated in 

 them. In one form or another it is found at nearly all the apatite open- 

 ings examined. 



At the top of the hills at High Rock, about 20 rods southeast of the 

 office, the exposed surface consists of a belt of pyroxenite inclosed in 



V V V V V ^ 



V V V V V, 



'^)j V y y 



r'iGLRK 2 —Dike of coarse Sycnitr-ecneiss ciitlinc: Quarlzilc and Pyi oxenilc. 



A mass of the quartzite is inclosed in the syenite. The pyroxenite appears as a dike intercalated 



in the quartzite. 



quartzite, witli a strike of south 30° east (magnetic). At one point there 

 is a slight linear depression covered with soil transverse to the strike of 

 the rock, which evidently re[)resents a fault. On the south side of this 

 depression the beds of quartzite and intercalated pyroxenite have been 

 shifted about two feet to the east. On tlie north side both pyroxenite 

 and quartzite are cut by a dike of coarse grained syenite in a direction 

 south 20° east (magnetic). After passing the sui)posed fault-line the dike 



