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NEW YORK STATE MUSEUM 



These limestones undoubtedly represent calcareous sediments 

 charged with magnesia, iron, silica and alumina, the latter elements 

 forming the various silicates during metamorphism. Graphite is 

 almost universally present. 



The intense metamorphic changes which result in great contortion 

 or complete crushing when applied to sandstone result in flowing and 

 recrystallization when applied to limestone. The crystalline lime- 

 stones of the Adirondacks have lost their original features and with 

 recrystallization have developed polysynthetic twinning, parallel 

 y 2 R. The limestone is thoroughly crystalline throughout its extent, 

 and its condition can not be explained as a result of contact meta- 

 morphism from the associated intrusions. Contact effects have been 

 described by various writers in various Adirondack localities, but on 

 the Paradox Lake quadrangle the contact metamorphism resulted 

 in changes in the intruded rock. 



The limestone is found in the wider valleys in long belts and in a 

 few isolated patches among the hills. One long strip of it lies along 

 the Paradox valley, while another forms the shores of Penfield 

 pond. Gneiss and schist are often interbedded with it, and the dip 

 can sometimes be discovered from these layers. The limestone itself 

 is so completely recrystallized that as a rule no bedding can be made 

 out. The only locality where a dip and strike could be determined 

 in the pure limestone was in a little canyon on the south side of 

 Paradox lake, where there was a little cave in the side of the cliff. 

 Similar caves are common, and so are little natural bridges and 

 other forms resulting from solution. * 



In the northwestern part of the Penfield pond limestone belt are 

 a series of little hills of limestone interbedded with gneiss. Near 

 Dudley pond the outcrop of alternating gneiss and limestone is 

 repeated by a fault, the beds here dipping gently east. Farther 

 south the limestone becomes purer ; its associated gneiss stands out 

 as several good sized hills, and no interbedding is seen. 



Mica schist. 1 Typically a biotite schist, containing occasionally 

 a little hornblende, and sometimes grading into a gneiss this rock 



Schists differ from gneisses in that they have finer laminations. They often 

 have the same mineral composition as the gneisses, but sometimes are more 

 basic. They are classified according to the principal dark silicate present. 



