114 NEW YORK STATE MUSEUM 



that exposed on the active graphite properties in the southern 

 region, there are some interesting variations. 



Above the ore is a bed of quartzite about 50 feet thick that is 

 evidently equivalent to the horizon called the Swede Pond quartzite. 

 On top of this quartzite is a bed of crystalline limestone which is 

 commonly siliceous and contains various green silicates that have 

 been changed to serpentine. It is about 50 feet thick and is sur- 

 mounted by another layer of quartzite. The question arises whether 

 this lime formation is equivalent to the so-called " sandy " lime- 

 stone which is shown on the southern edge of the Dixon-Faxon 

 properties. If this is the case then it is a little difficult to explain 

 the second stratum of quartzite. Thus it is proposed that this 

 limestone be called the Trout Pond limestone and the two quartzite 

 formations be called the lower and upper Swede Pond. It is of 

 course possible that the Trout Pond limestone is replacing the 

 Swede Pond quartzite in somewhat the same way that the Faxon 

 limestone was found to do on the International Graphite Com- 

 pany's property. On the southern slope of the prominent ridge 

 that limits the valley on the west a quartzite-carrying graphite was 

 encountered. It is possible that this is the Bear Pond schist which 

 constitutes the ore on the Bly property, or this graphite may have 

 been introduced into the Swede Pond by the action of adjacent 

 igneous rocks. From a study of a thin section cut from this 

 material, the writer concludes that the former interpretation is 

 probably the correct one. The so-called sandy limestone is either 

 absent or so highly silicified that it could not be recognized as 

 such. At the Flake Graphite Company's mine (Greenfield, Sara- 

 toga county) a parting composed of limestone and green quartzite 

 separated the ore into two distinct layers. On the Smith property 

 a thin stratum of limestone occurs near or on top of the graphitic 

 member. 



Beneath the ore is another limestone that seerns to be a new one 

 in Grenville stratigraphy. While it is conceivable that this may 

 be a phase of the Faxon it is deemed best to introduce a new term, 

 the Chesterfield limestone. This is some 50 feet thick. There is 

 some uncertainty in regard to the rock that lies beneath the Chester- 

 field, as exposures are very rare. In the core of the anticline 

 loose boulders of a para-amphibolite were encountered in sufficient 

 numbers to justify the conclusion that they came from a bed situated 

 beneath the limestone. No evidence could be secured that the 

 garnet-sillimanite gneiss of the southern area, named the Hague 

 gneiss, was present. 



