AMERICA. 



123 



Bay, whether identical with those of the southern shore or not, and 

 whether Paleozoic or Mesozoic, are really newer than the adjacent cupri- 

 ferous amygdaloids, and are not to be confounded with the sandstone 

 strata which, on both sides of the lake, are found interstratified with 

 these, and provisionally adopts Prof, liell's name of " Nepigon Group" 

 for them. W. W. 



Hunt, Dr. T. Sterry. The Ore Knob Copper Mine and some Related 



Deposits. Trains. Amer. Inst. Min. Eng. vol. ii. pp. 123-131 (with 



discussion). 

 This mine, in N. Carolina, is on a true fissure-lode, cutting the 

 gneiss and mica-schist, which dip 45°S.E., the lode being vertical, with 

 a course N. 60° E. Both country rock and lode are decomposed to 

 some depth. At a certain depth the porous gossan is charged with 

 carbonate and red oxide of copper, and lower down is replaced by rich 

 sulphuretted ores. The outcrop has been traced for 1900 feet ; and the 

 breadth of the lode varies from 6 to 14 feet. The lode is compared 

 with others in Tennessee and Virginia, regarded as deposits of later date 

 than the beds in which they occur. W. W. 



. The Coals of the Hocking Valley, Ohio. Trans. Amer. Inst. 



Min. Eng. vol. ii. pp. 273-278. 

 This may be taken as included in the pamphlet of 1874, noticed in 

 the Geological Record for that year, p. 120. 



. The Decayed Gneiss of Hoosac Mountain. Proc. Boston Nat. 



Hist. Soc. vol. xviii. pp. 106-108. 



IngersoU, Ernest. The Sand-dunes of the San Luis Valley. Amer. 



Nat. vol. ix. pp. 375, 376. 

 Shows how the action of the wind on these sand-dunes produces 

 appearances like those seen on sandy beaches. 



Irving, Roland. Note on some New Points in the Elementary Stra- 

 tification of the Primordial and Canadian Rocks of South Central 

 Wisconsin. Amer. Journ. ser. 3, vol. ix. pp. 440-443. 



Tabulates the equivalence of the divisions of these systems thus : — 



Cana- 

 dian. 



Primor- 

 dial. 



S. Central Wisconsin. 



St. Peter's Sandstone. 



Main body of Limestone, 

 80 to 120 feet. 



Madison Sandstone, 35 ft. 



Mendota Limestone, 30 ft. 



Lower or Potsdam Sand- 

 stone. 



Mississippi Bluffs. 



St. Peter's Sand- 

 stone. 



Lower Magne 

 sian Lime- i 

 stone, 200 to "^ 

 250 ft. 



Lower or Potsdam 

 Sandstone. 



Minnesota River. 



St. Peter's Sandstone. 



Sbakopee Sandstone, 

 70 ft. 



Jordan Sandstone, 

 50 ft. 



St. Lawrence Lime- 

 stone. 



Lower or Potsdam 

 Sandstone. 



G. A. L. 



