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MOW VOKK SlAllC Ml'SKlM 



TALC 



Talc deposits, remarkable for their size and character, are found 

 in St Lawrence county. They are exploited on a large scale and 

 furnish most of the ground talc used in this country, besides a 

 considerable quantity for export. The product is commonly sold 

 under the name of mineral pulp, which is suggestive of its principal 

 application; nuicli of the talc has a fibrous texture that is preserved 

 even after fine grinding and this feature makes it particularly 

 valuable for incorporation in paper stock. Foliated talc which 

 occurs in subordinate quantity, is also produced to some extent by 

 the mines. 



Features of the occurrence. The supply of fibrous and foliated 

 talc is obtained from a single district, in southwestern St Lawrence 

 county. Geologically the limits of the district can be quite sharply 

 defined. The talc is associated with crystalline limestones and 

 schists of Grenville age. which occupy a belt some 12 miles long and 

 from I to 3 miles wide extending in a northeasterly direction 

 nearly across the towns of Fowler and Edwards. The belt is in- 

 closed by gneisses, largely of granitic and dioritic composition, no 

 doubt in part at least of igneous derivation ; while dark hornblendic 

 gneisses of uncertam origin are not uncommon. A small area of 

 the gneisses is included in the central part of the belt with the 

 Grenville bordering it on all sides. 



The talc deposits occur along minor belts within the limestones 

 and tremolite schists. They are locally described as veins, but 

 really have nothing in common with them, being beds or layers 

 interstratified with the limestones. They have the same strike and 



