GEOLOGY OF THE LUZERNE QUADRANGLE 33 



well- foliated gray granite cutting much limestone and some 

 pyroxene gneiss. 



In the very small area south of Thurman station a single large 

 outcrop by the river is an irregular mass of well-stratified highly 

 folded impure crystalline limestone about 25 feet across almost 

 completely surrounded by grano-syenite (see plate 7A). 



The mixed rocks of the small area just west of High Street are 

 Grenville gray garnetiferous gneisses intricately cut and injected by 

 granite. 



In the small area just northwest of Athol much impure graphitic 

 crystalline limestone is directly associated with some hornblende- 

 garnet gneiss. Both of these rocks are irregularly cut by much 

 granite. 



South and west of Bear pond considerable crystalline limestone 

 and some quartzite are cut by pink medium-grained granite. 



Grenville-gabbro-granite Mixed Rocks 



In a few relatively small areas Grenville strata, gabbro (meta- 

 gabbro), and granite are so closely associated that it has not been 

 feasible to represent these rocks separately on the geologic map. 

 The area at Hadley and Luzerne shows a number of exposures 

 which give a good idea of these mixed rocks. The largest ex- 

 posures are along the river, along the outlet stream of Lake 

 Luzerne, and in the southern part of Luzerne village. These rocks 

 are gray, garnetiferous, biotitic, Grenville gneisses associated with 

 bands or lenses of amphibolite, cut and considerably injected with 

 granite and pegmatite mostly parallel to the foliation. The com- 

 bination presents a well-banded appearance generally with steep 

 dips. Usually the Grenville material predominates, but along the 

 outlet stream of the lake there is more granite than Grenville. 



The Constitution mountain area contains more or less intimately 

 associated Grenville, metagabbro and granite in varying amounts. 

 Metagabbro is most conspicuous toward the south where it occurs 

 in the form of numerous bands in the mixed rocks. The Grenville 

 portions of these mixed rocks are generally garnetiferous. 



The area south of Gailey hill shows many good exposures of 

 mainly well-banded (straight to curved) garnetiferous, biotitic 

 Grenville gneiss cut and notably injected with granite, pegmatite 

 and silexite, the whole containing bands or lenses of amphibolite 

 (metagabbro) ranging from mere shreds to a rod or two wide and 

 some rods long. Lofzallj the relative proportions of these rocks 



