GEOLOGY OF THE LUZERNE QUADRANGLE 3I 



Linwood school, and one-half of a mile east-southeast of Linwood 

 school, but many of the bands of highly foliated granite are there 

 pink and moderately coarse grained.^''^ 



Among other places where typical straight banded, alternately 

 white to dark gray, biotitic, garnetiferous Grenville-granite mixed 

 or injection gneisses like those above described may be well seen 

 are in great ledges in a small gorge at the road corners i mile west 

 of Efner lake; along the road between i^ and 2^/2 miles west of 

 Efner lake ; one-half of a mile northwest of Efner lake ; many ex- 

 posures throughout the large area west of Conklingville where por- 

 tions of the typical garnetiferous mixed rock very locally contain 

 some thin bands of amphibolite, pegmatite and silexite parallel to 

 the foliation; throughout the area i^ miles east of Conklingville; 

 the lower two-thirds of the ledge 100 feet high with highly foliated 

 quartz syenite or quartz diorite with low dip resting upon the mixed 

 rock at the dam across the Hudson river at Palmer ; along the road 

 for ly-i miles across the mixed rock area southwest of Hartman; 

 and along the road 15^ miles north-northeast of Palmer. 



In addition to the type of Grenville-granite mixed rock above 

 described, there are considerable bodies of more irregularly mixed 

 and less digested rocks. This is especially true in the large area 

 in the southeastern part of the quadrangle except along the road 

 across the south side of the area. In the eastern part of this area, 

 and also on the hill i^ miles west-northwest of Hartman, the rocks 

 are rather irregularly banded, dark gray, biotitic, garnetiferous 

 Grenville-granite mixed rocks locally associated with some am- 

 phibolite and pegmatite. The Grenville material seems to predomi- 

 nate, but the bands are not conspicuously light and dark. Similar 

 mixed rocks occur in the northwestern part of the area with a short 

 narrow belt (10 feet wide) of pure Grenville quartzite at one place. 



The small area just west of the railroad 2 miles south of Luzerne 

 shows mostly dark gray, garnetiferous Grenville involved with a 

 little amphibolite and more or less intricately cut by granite and 



^"^ Since the preparation of this manuscript, field work by the writer in the 

 Gloversville quadrangle has led to the tentative conclusion that banded garneti- 

 ferous gneisses very similar to those here described have at least partly resulted 

 from more or less intimate injection or assimilation of an amphibolitic facies 

 of old gabbro by the syenite-granite magma. As already suggested on page 

 17 some (or much) of the injected amphibolite may be of sedimentary origin. 

 The highly banded garnetiferous gneisses here described m^y possibly, there- 

 fore, be partly or wholly metagabbro-granite mixed rocks., During the field 

 season of 1923, the writer hopes to secure evidence which will throw more 

 light upon the problem of the origin of these rather widespread garnetiferous 

 gneisses. 



