GEOLOGY OF THE LUZERNE QUADRANGLE I3 



south of the corners there are good exposures of Grenville horn- 

 blende-garnet gneiss. Farther south, including the narrow tongue 

 which extends into the granite (see map), there are good outcrops 

 of the usual limestone mixed or interbedded with more or less 

 hornblende-garnet gneiss. For one-fourth of a mile along Number 

 Nine creek toward the western end of the Athol area, there are ex- 

 cellent outcrops of Grenville biotitic, pyroxenic, and hornblendic 

 schists and gneisses, mostly thin-bedded, with some bands of lime- 

 stone a few feet thick interstratified. Nearly all this rock is 

 straight banded with a dip of 25 degrees to the northeast, though 

 a few local contortions do occur. Locally these rocks are cut and 

 somewhat injected by a little granite and pegmatitic granite. At 

 the southern border of the area nearly a mile east of High Street, 

 a big exposure consists of well-bedded Grenville quartzite showing 

 a thickness of about 15 feet with some poorly exposed limestone 

 on top. Grenville limestone of the usual kind is well exposed in the 

 southern part of the area between the small body of gabbro and 

 the tongues of granite to the northwest (see map). 



In the small area just north of the road nearly a mile southwest 

 of Thurman station, there is an old quarry in which Grenville 

 pyroxenic crystalline limestone is well exposed. 



The Grenville a mile east of Bear pond contains mostly hard, 

 heavy, hornblende-garnet gneiss locally associated (on the east 

 side) with some limestone and a little pyritous (" rusty ") schist. 



The Bear pond area marks the southern end of a large body of 

 Grenville limestone of the North Creek quadrangle. Several good 

 exposures of the limestone, cut by a little granite, occur southeast 

 of Bear pond. 



Boldly outcropping in the little valley west of Wolf pond there 

 is a large mass of Grenville crystalline limestone. The small hill 

 of solid rock really consists of limestone cut by numerous dikes of 

 silexite. The crystalline limestone is medium-grained and white 

 with scattering lumps of pale green serpentine representing altered 

 original pyroxene. Much of the limestone is more or less con- 

 torted, and it is cut by a network of nearly pure white silexite 

 (quartz) dikes which constitute perhaps one-half of the hill. The 

 boldness of the outcrop is due to the resistance of these dikes. 



Areas southwest of Warrenshurg village. Five small areas of 

 Grenville are shown on the map within a few miles to the south- 

 west of Warrensburg. Largest of these is the area across the river 

 from Thurman station. At the edge of the river, near the western 



