GEOLOGY OF THE SCHROON LAKE QUADRANGLE 15 



sists of interbedded quartzite (some garnetiferous), quartz-pyrox- 

 ene gneiss, and quartz-feldspar gneiss with several thin layers of 

 limestone containing green pyroxene. 



The area just east of North pond shows a number bf good 

 exposures of well-bedded hornblende-garnet gneiss and hornblende 

 gneiss with one two-foot thick layer of limestone in the horn- 

 blende gneiss. Near the western corner of the area there are many 

 large reddish brown garnets up to 4 or 5 inches in diameter, but 

 without hornblende rims as is often the case with such large garnets 

 in the Grenville hornblende-garnet gneiss elsewhere in the 

 Adirondacks. 



Other areas of Grenville. In the small area on the west face of 

 Wilson mountain, pyroxenic, hornblendic and quartzitic gneisses are 

 well exposed, some of these being locally contorted. Along the 

 eastern side of this area the Grenville rocks are more or less inti- 

 mately charged with granite. 



At the western end of the area just southwest of Oliver pond 

 there is a big exposure of hornblende-garnet gneiss interstratified 

 with thin-bedded, fine grained, pinkish gray, quartz-biotite schist. 

 A few rods farther east there occurs a ledge of limestone con- 

 taining green pyroxene, quartz and a little graphite. Toward the 

 eastern end of the area the rock is hornblende-garnet gneiss. 



A small lenslike inclusion of hornblende-garnet gneiss with gar- 

 nets up to an inch across occurs in the granite one-half of a mile 

 west of Oliver pond. 



One mile northeast of Loch Muller, 1 in the small area mapped, 

 there is a single large outcrop of hornblende gneiss, somewhat 

 garnetiferous. 



On the southern slope of Hayes mountain, three-fourths of a 

 mile from its summit, a small lenslike body of typical hornblende- 

 garnet gneiss with garnets up to an inch across occurs as an 

 inclusion in granite. A similar small inclusion occurs in the syenite 

 2 miles north-northwest of Irishtown, and still another in granite 

 i l /4 miles west-southwest of the summit of Hayes mountain. 



is the place printed on the map accompanying this bulletin, but 

 since the map was printed the post office has been moved 2 miles to the 

 northwest to Warren's hotel. 



