GEOLOGY. 255 



tus for economical purposes, reveal its presence in great quantity. 

 Much of it is soft, of a grayish-white color, composed of delicate 

 parallel fibres often a foot in length, with a marked cross cleavage 

 oblique to the fibres, as in hornblende. 



Intimately associated with the asbestus is an altered mica allied 

 to vermiculite or jefferisite. It differs, however, in certain phys- 

 ical characters from the jefferisite of Westehester, Pa., but seems 

 to resemble it in its optical characters. There also occurs, at the 

 same locality, a white corundum, sometimes streaked with blue, 

 and occurring in nodules of corundophillite. It occurs in small 

 quantity, but farther excavations promise to afford it in greater 

 abundance. Amer. Jour. Science, March, 1870. 



Native Iron and Lead. At a meeting of the American Philo- 

 sophical Society, Dr. Gcnth showed specimens of native iron and 

 native lead from the bed-rock of gold-placers covered with about 

 6 feet of gravel, at Camp Creek, Montana Territory. The 

 native iron is found in small, angular fragments, but slightly 

 coated with rust ; the largest which he has seen is about 0.5 inch 

 in length. Etching with dilute nitric acid does not develop any 

 Widmannstsedtean figures, but a finely granular structure. The 

 lead was examined for nickel and cobalt with negative results. 

 Associated with the iron is native lead, in irregularly shaped 

 rounded and flattened pieces from the size of a pin's head to about 

 0.5 inch in diameter. The lead is coated with a crystalline coat 

 of massicot, of a sulphur-yellow to reddish-yellow color; some 

 pieces also show very brilliant but microscopic crystals, which 

 may be cenissite. Acetic acid dissolves this massicot, and leaves 

 the metallic lead, which then shows its crystalline structure. The 

 lead showed traces of gold, but no silver. 





