1S67.] MACFARLANE— GEOLOGY OF LAKE SUPERIOR. 



183 



and the latter varies from 1-1° to 20° north-westward. It is 

 in t erst ratified with a small-grained granitic gneiss, containing 

 much less mica than the last — about one-twentieth only, — no 

 tricliuic felspar, and having a specific gravity of 2-71 to 2-72. 

 The same granitic gneiss intersects the characteristic gneiss in 

 veins, and both of these rocks are cut by a coarse-grained granite, 

 almost destitute of mica, and completely so of schistose structure. 

 The strata of the gneiss are much contorted in various places. 

 The intersecting granitic gneiss and granite are almost equal in 

 quantity to the gneiss itself; and although they occur as irregular 

 veins, they are, at the point of junction, as firmly united with 

 the gneiss as any two pieces of one and the same rock could 

 well be. Figure 3 is intended to represent the relations 

 observable at Goulais Falls. Between Goulais Falls and the 



Fie. 3. 



a = = 







a. Gneiss. | b. Granitic gneiss. | c. Coarse-grained granite. 



point where the line of junction between the Laurentian and 

 Huronian rocks crosses Goulais River, there are numerous 

 exposures of gneissoid rocks, but characteristic gneiss is of rare 

 occurrence among them. At several places hornblende schist, 

 in fragments, is observed enclosed in a gneissoid granite. Some 

 of them are longer than others, and have their longer axes 

 running N. 50° to 60° W. Hand specimens of the enclosing 

 granite show little or no mark of foliation, but when seen in 



