GEOLOGY OF THE SCHROON LAKE QUADRANGLE 49 



particularly fine exposures on the eastern slope of Bailey hill, and 

 along the middle of the crest of Washburn ridge. 



Certain localities of special interest in the larger area will now 

 be described. One of these is along the brook 2 miles northeast 

 of Bailey pond. By the trail there is a large outcrop of peculiar, 

 variable rock. There are some small patches of Whiteface anor- 

 thosite embedded, but most of the rock has a granitoid texture and 

 contains scattering bluish gray labradorites up to an inch long (see 

 no. 29 of table 3). This latter rock looks much like the Cobble 

 hill rock above described except for fewer labradorites, and it is 

 considered to be Keene gneiss with a history similar to that on 

 Cobble hill. Just across the brook to the east there is a big ledge 

 of very highly foliated medium-grained granite gneiss with both 

 the quartz and feldspar highly flattened out parallel to the foliation. 



An interesting lot of rocks occur on Washburn ridge i mile 

 north-northeast of Bailey pond. A little to the north of this local- 

 ity (see map) a considerable body of typical Whiteface anorthosite 

 is exposed. A few rods to the south of the anorthosite there are 

 exposures of mostly distinctly gneissoid rocks, syenitic in appear- 

 ance but containing tiny garnets and some large bluish labradorites, 

 these latter not always being arranged parallel to the foliation. 

 No. 30 of table 3 represents a thin section of this rock, but none 

 of the labradorite happened to appear in the section. This rock 

 is quite certainly Keene gneiss. Some portions of these same ledges 

 strongly suggest rather gabbroid garnetiferous facies of Whiteface 

 anorthosite. A few rods still farther south, typical granitic syenite 

 is exposed as shown on the geologic map. A careful study of these 

 ledges on Washburn ridge strongly supports the view that White- 

 face anorthosite has there been acted upon by granitic or syenitic 

 magma, some of the anorthosite having remained unaffected, some 

 having been partially assimilated, and still others completely assimi- 

 lated, while unaffected granitic syenite outcrops at the south. The 

 actual extent of the granitic syenite here is unknown because no 

 exposures of any kind occur for fully a mile to the south. On the 

 crest of the southern portion of Washburn ridge, and continuing 

 for one-half of a mile north from the area of Whiteface anorthosite 

 (see map), a somewhat variable, medium to fine-grained, basic, 

 syenitic-looking rock full of tiny garnets shows in good exposures. 

 Though large labradorites are absent, this rock is thought to have 



