38 



NEW YORK STATE MUSEUM 



mountains to the westward. It outcrops in typical development at 

 Split Rock falls, where in the cascades of the Boquet it is ' well 



\ft ti-U, 



"Fig. 5 Two inclusions of anorthosite in Spl^t Rock Falls type, at Split Rock falls 



-exposed. The rock is suggestive of the anorthosites in that blue 

 labradorite is the chief feldspar present, but the dark silicates are 

 more abundant and when crushed and sheared the rock yields a 

 decidedly foliated gneiss. It then becomes a hard dense rock, ex- 

 tremely tough. Nevertheless, large phenocrysts of labradorite are 



