186 PALEOZOIC TIME. 



able in the world. The copper is mostly in the native state, or pure 

 copper, and occurs in great masses or sheets, as well as in strings 

 and grains. The strings are really made up of imperfect crystals. 

 One great sheet of copper, opened to view in the course of the 

 mining, was forty feet long, and weighed, by estimate, two hundred 

 tons. Much of the copper contains native silver, in imbedded grains, 

 often large enough to be visible, and sometimes an inch or more 

 across ; some specimens are spotted white with the more precious 

 metal. 



In addition to copper, the rocks contain the usual trap minerals, — 

 zeolites, datolite, calcite, quartz ; and some calcite, datolite, and anal- 

 cite crystals are implanted on or about threads of copper, showing 

 that they are of subsequent origin. The copper occurs in irregular 

 veins in both the trap and the sandstone, near their junction ; and, 

 whenever the trap was thrown out as a melted rock, the copper prob- 

 ably came up, having apparently been derived from copper-ores in 

 some inferior Archaean rocks, through which the liquid trap passed 

 on its way upward. The extent to which the rock and its cavities 

 are penetrated and filled with copper shows that the metal must have 

 been introduced by some process before the rock had cooled. 



There are also rich silver mines. " Silver Islet," adjoining the 

 north shore of Lake Superior, is already a noted mining region ; the 

 ore deposits have been found to be continued over the country to the 

 north. 



In Eastern Canada, copper ores have been observed in upward of 500 localities in 

 rocks of the Quebec group. The ores are the yellow sulphid or chalcopyrite, chalco- 

 cite (vitreous copper) and bornite. There are also many localities along the north 

 shore of Lake Superior. 



The Quebec group also affords, in Canada, magnetic and specular iron; chromic iron, 

 in serpentine, of workable value, one bed, in Ham, three to four feet thick; native 

 antimony and other ores of this metal, in Ham. 



The lead mines in Washington, Jefferson, and Madison Counties, Missouri, and in 

 Arkansas, occur in the Lower Magnesian limestone. In Jefferson Count}'', Missouri, 

 as also in Tennessee and southwestern Virginia, the ores of zinc, calamine, and smith- 

 sonite, as well as blende, occur with the lead ore or galenite. 



Quartz crystals occur in great abundance in cavities in the Calciferous sandrock 

 of central New York and East Tennessee, and fissures are often lined with them. A 

 kind of mineral coal, in small lumps, usually concretionary in structure, is found in 

 some of the beds ; and fragments are often imbedded in the crystals of quartz, or lie 

 loose in the cavities that afford the crystals. 



III. Life. 



The living species of this period belonged to the same grand 

 divisions as those of the Primordial. The plants thus far discovered 

 were all Algae or sea-weeds ; and the animals were all marine Inverte- 

 brates, they belonging to the four sub-kingdoms, Protozoans, Radiates, 

 Mollusks, and Articulates. 



