THE ADIRONDACK C.RAl'IMTK DKI'OSITS 



61 



Rock pond workings. These consist of an abandoned pit about 

 150 feet in diameter and 40 feet deep, filled with water, and a 

 drainage tunnel. The rock is chiefly a feldspar schist (an 

 " arkosite m ) carrying graphite and heavily impregnated with pyrite 

 which carries traces of galena. The oxidation of the former mineral 

 to various oxides, hydroxides and the sulphate of iron has deeply 

 stained the walls of the pit with reds, yellows and browns, with 

 splashes of white incrustations of copperas. 



Geology and structure. The geology in essence is not very com- 

 plicated but with the isoclinal folding and subsequent compression 

 followed by igneous injection, the structure is very involved. 



W5\ B 



: 



SYENITE-GRANITE 

 META-GABBRO 



PARA-AMPHIBOLITE 



.'GRAPHITIC SCHIST 



TljiTO CATAMOUNT SCHIST 



SANDY QUARTZ\TE 



Fig. 11 Vertical section of the Bear Pond Mountain region, showing 

 the isoclinal folding of the Bear Pond schist and associated rocks. 

 H. L. Ailing, 1917. 



Bear Pond mountain is probable an anticline (see section, figure 11), 

 while the south side of the hill is a syncline, both strongly pitching 

 westward. These folds have been truncated by erosion, so the line 



1 The term arkose is the " special name for a sandstone rich in feldspar frag- 

 ments, as distinguished from the more common, richly quartzose varieties." 

 (Kemp, J. F., " Handbook of Rocks," 1911, p. 187). The term "arkosite" 

 is proposed to signify an arkose that has been metamorphosed into a rock 

 analogous to quartzite. 



