88 RURAL MICHIGAN 



and railroad construction. Surveys were continued 

 at intervals for many years and even now the Geo- 

 logical Survey of Michigan undertakes from time 

 to time field work that, it is hoped, will reveal addi- 

 tional resources that may enrich the commonwealth. 



Unlike iron, copper made its presence known to 

 the first explorers of the Lake Superior country, and 

 had hitherto been extensively utilized by the Indians 

 in the manufacture of weapons and utensils, of which 

 there are several notable collections both within and 

 without the State and which are still being increased 

 by occasional discoveries here and there throughout 

 the district. Michigan copper, unlike that found 

 in Montana, Arizona, Utah and many other places, 

 is a formation of pure copper uncompounded with 

 other elements. Rarely it forms a metallic cement 

 combining pebbles in a conglomerate formation. 

 More commonly it is dispersed through the rock in 

 large masses and in granules, frequently at great 

 depths below the surface, but occasionally exposed 

 on the surface itself. It was these exposed masses 

 of copper that engaged the attention of the early 

 Jesuit and other French and English explorers. 



The native mining operations suggested locations 

 for similar enterprises by the whites, as in the case 

 of the Isle Eoyale Mine at Houghton. In Michigan 

 the copper veins were distributed along a rather 

 narrow axis from Porcupine Mountain near the Lake 

 Superior shore westward from the Keweenaw Penin- 

 sula and near the center line of this peninsula for 

 quite its entire length, with points of major dis- 



