PLATE IV. 



FlG. I. COPPER FOUND AT WORTH, ILL.; WEIGHT, 13 LBS. ; PARTLY CRUSHED IN- 

 STONE CRUSHER; Now OWNED BY OSSIAN GUTHRIE. 





FIG. 2. CRYSTALS OF PYRITES IN NIAGARA LIMESTONE; EXPOSED IN LEFT HAND 

 SPECIMEN BY DISSOLVING AWAY THE LIMESTONE IN HYDROCHLORIC ACID. 



