ELIZABETHTOWN AND PORT HENRY QUADRANGLES 



39 



not uncommon and the gneiss often exhibits the '' aiigen '' produced 

 from them. 



ATiortKoslte Gabbro &neis5 



Fig. 6 Inclusions of anorthosite in gabbro of the Split Rock Falls type. Ledges on 



Slide brook 



This intrusive is known to be later than the anorthosites because 

 in the bare ledges along the cascades at Split Rock falls, inclusions 

 of anorthosite are found in it. Each is surrounded by a garnet 

 rim which appears to represent magmatic or corrosion phenomena. 



Woolen Mill locality. On the south side of the Branch a mile 

 to the west of Elizabethtown and near the mill there is a' very 

 interesting rock which exhibits an irruptive contact with the anor- 

 thosite and extends both westward and southward. It is dark, 

 gneissoid and of moderate coarseness of grain. It resembles a 

 rather basic member of the syenite series but has occasional blue 

 labradorite phenocrysts which ally it with the anorthosites. Under 

 the microscope and in slides from specimens without the labra- 

 dorite phenocrysts, the minerals are, rather deep green pyroxene, 

 sometimes showing faint pleochroism to yellow, plagioclase, ortho- 



