2B,S NEW YORK STATE MUSEUM 



along the strike and dip are measured usually by hundreds of feet. 

 The thickness is greatest ordinarily near the middle of the deposit 

 as seen on the surface and gradually diminishes in either direction. 

 The extent of the deposits on the dip is unknown, but exceeds the 

 depths attained by mining up to the present time, which are about 

 700 feet in the deepest shafts, measured on the plane of the dip. 



The talc bodies are distributed mainly along the borders of the 

 limestone area, in the section from Sylvia lake to Edwards. Although 

 they occur rather irregularly, most of the deposits may be grouped 

 into two main belts extending northeast-southwest parallel with the 

 limestone-gneiss contact. One of these is in the southwestern end 

 of the district and on the southern margin of the limestones. Within 

 it lie the Baknat, Wight and Arnold mines, of the former Union 

 Talc Co., recently operated by the International Pulp Co., and the 

 mine formerly worked by the Ontario Talc Co., also the shaft and 

 prospects on the property of the Dominion Co., near Sylvia lake, 

 northwest of the Baknat. This belt is about 3 miles long and the 

 talc occurs within a short distance of the gneiss foot wall which 

 here consists of a dark amphibolitic rock that is injected by red 

 granite. The second belt is northeast of the first and on the 

 opposite side of the limestone area; the strata here dip below the 

 gneiss, which also is an injected type, and contain the mine of the 

 Uniform Fibrous Talc Co., on the Oswegatchie river below Talcville, 

 the old United States mine at Talcville, and the several openings 

 of the International Pulp Co., including Nos. 25, 3, 4 and 5, in the 

 stretch between Talcville and the first mile northeast of that village. 

 It is not uncommon to find two or more layers of the talc, in over- 

 lapping arrangement. As many as four parallel layers are known 

 at a single locality, separated by intervals of unchanged tremolite 

 and of limestone. In the exploitation of the deposits it has been 

 found that the pinching out of a body as it is followed along the 

 strike or dip may be accompanied by the appearance of a second 

 layer in the hanging or foot wall which can be tapped by a short 

 cross-cut. 



Mining practice. Mining is carried on underground, although in 

 the early days open-cut methods were in use on the outcrop of the 

 deposits. The general practice in the district does not differ materi- 

 ally from that followed in working ore deposits that are similarly 

 situated, though of course the soft and slippery nature of the material 

 necessitates certain modifications, especially in regard to pillar 

 supports which have to be of large size. The workings are reached 

 through inclines carried down on the footwall. If the bed is not over 



