and Igneous Rocks of Ensay. 



75 



and its chloritic alterations, together with a considerable 

 amount of quartz, making up the remainder of the rock. 



This rock is one of the characteristic schists of the district, 

 and in its unaltered condition must have been a gneiss rich 



A quantitative analysis of this sample gave me the follow- 



ing results : — 







No. 3.— 



Metamorphic 



Gneiss. 



P 2 3 



... 



•10 



Si.O, 



. . . 



... 5594 



A1. 3 3 ... 



. . . 



... 23-39 



FaX ... 



. . ■, 



•45 



Fe.O 





... 4-69 



Ca.0 





'81 



Mg.O 



. . . 



... 3-58 



K,0 



... 



... 6-98 



Na. 8 



. . . 



... 345 



H 2 6 



moisture 



... 3-60 





100-99 



Hygroscopic 



... -43 



Sp. grav. 







... 2-777 



Not far up stream from this place the river-bed becomes 

 rocky, and affords an admirable study of the formations. 

 From this spot I made a careful examination of the succes- 

 sive rock-masses for some distance, both up the Little River 

 and Watts Creek. In order to fully note and illustrate the 

 peculiar features of these rocks, I shall now describe them 

 with some fulness. The numbers given refer to those upon 

 the accompanying plan, Pi ate I. 



1. — These schists are much distorted, and contain irregular 

 quartz foliations. The foliations of the schist appear to 

 coincide with former planes of deposit, and strike N. 

 35° to 40° W. Under the microscope this rock proves 

 to be a quartzose schist, with a little triclinic felspar, 

 two kinds of mica, and some pinite masses. The quartz 

 forms foliations of irregularly-shaped grains. 



The felspar is also in irregularly-shaped grains, resembling 

 fragments of crystals. They are numerously compounded, 

 and have the appearance of albite or oligoclase, and those 

 obscuration angles which I could measure were low, being 



