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NEW YORK STATE MUSEUM 



rather difficult to 'determine. In the main workings which lie near 

 the summit of the ridge to the southwest of the mill the bed ranges 

 up to 25 feet or more thick and is worked partly under cover and 

 partly as an open cut. 



The matrix of the graphite is a thin-bedded schist, carrying a 

 good deal of feldspar and sporadically more or less mica, in addi- 

 tion to quartz. It is rather heavily charged with pyrite and the ex- 

 posed edges of the beds have been decomposed into an iron-stained 

 clayey material which is relatively enriched with graphite. The 

 flake varies in size, a good proportion being fairly coarse. Plans 

 have been considered for increasing the output, which will necessi- 

 tate an addition to the milling plant but little change in the mine 

 equipment. 



Hooper Brothers' mine. This is a new property, situated in the 

 vicinity of South bay, west of Whitehall, Washington county. The 

 first development work was undertaken in the late summer of 1916 

 by the present owners, Messrs F. C. and George Hooper, and so 

 rapidly was the development and construction work carried forward 

 that the property was ready for commercial operations in the early 

 part of 191 7. The deposit combines many advantages for economic 

 production, and it seems remarkable in view of its size and exposed 

 situation — lying within the narrow peninsula between Lake George 

 and Lake Champlain — that the deposit should not have been 

 brought to attention long ago. The outcrop of the graphite bed is 

 on the northern flank of the ridge called the " Diameter " which 

 rises from the western shore of South bay, about 4 miles due west 

 from Whitehall, which is the shipping point. The old Burgoyne 

 road, built by the British general of that name, crosses the property. 



On the south side of Diameter, next the bay, is the mine of the 

 Champlain Graphite Co., now inoperative, no doubt located on the 

 same bedded series but under much disturbed conditions, due to 

 faulting and igneous intrusion. The deposit on the Hooper Broth- 

 ers' property outcrops along a low ridge facing north with a con- 

 tinuous exposure for over 3000 feet ; for much of the distance the 

 exposed edge forms a steep wall, of which the base is formed by 

 garnet gneiss conformable with the graphite schist, while the ridge 

 is capped by a sheet of gabbro that apparently was intruded along 

 the bedding planes of the schist overlying the graphite and later 

 uncovered by erosion. The whole series dips to the south at an 

 angle of 20 or so. The layer of graphite schist measures 40 feet 

 or more in maximum thickness. Samples have returned up to 

 15 per cent graphite, but the average of course is less by several 



