ECOLOGY OF NORTHERN MICHIGAN. 19 



PART I. PORCUPINE MOUNTAINS. 



1. HISTORY. 



The Porcupine Mountains are situated in the Northern Peninsula of 

 Michigan, in Ontonagon County, near the west end of Lake Superior, be- 

 tween the Iron and Presque Isle rivers. They were acquired by the United 

 States Government from the Mississippi and Lake Superior Chippewa Indians 

 by virtue of a treaty concluded October 4, 1842. The territory included 

 in this treaty was bounded on the north by Lake Superior; on the east by 

 the Chocolate river; on the south by the Michigan- Wisconsin boundary 

 line, and on the west by the Montreal river. Isle Roy ale was also included. 



Shortly after the treaty was concluded, prospecting was begun, and 

 during the period that followed the speculative fever ran high. The mere 

 presence of trap rock was taken as an indication of the presence of valuable 

 lodes of copper, and all the trap in the Porcupine Mountain region was soon 

 secured by permits. Many shafts were sunk, especially in the first range 

 where the junction of the trap and sandstone outcrops on the face of a cliff. 

 It was soon found, however, that in this region there are no well defined 

 lodes, the copper being scattered promiscuously in irregular seams through 

 the trap. Before the expiration of the year 1848, according to Foster and 

 Whitney ('49-' 50, p. 80), nearly all of the companies had abandoned their 

 locations, and there was scarcely a white man left in the region. 



The workings, with the exception of three or four, were little more than 

 prospect holes, and the impressions left upon the country by the presence 

 of man have nearly all been obliterated. In this condition, the mountains 

 have remained for fifty years. All about them the adjacent country has 

 been lumbered, but, owing to the fact that the pines do not occur in extensive 

 tracts, that the streams are not suitable for logging, and that up to a few 

 years ago it was not thought worth while to lumber hardwoods and hemlock, 

 the forests have thus far escaped destruction. With the exhaustion of the 

 pine in Michigan, however, and the consequently increasing price of lumber, 

 it has become profitable to lumber this timber, and the forests are being 

 rapidly taken off of the Northern Pejiinsula. The lumbering about Onton- 

 agon has nearly reached the great belt of hemlock on the east and north 

 slopes of the first range. The extensive possessions of the mining companies 

 will protect these forests for a time, but, with the increasing demand for 

 lumber, it will be but a few years until these magnificant forests will be 

 destroyed. 



2. GEOLOGY. 



It is not the purpose of this report to go into detailed discussion of the 

 geology of the region in question. It is necessary, however, to have a general 

 idea of the geological structure in order to understand the topography, for 

 the topography is largely due to the different degrees of resistance offered 

 by the outcropping rocks to erosion. The structural geology of this part 

 of Michigan has been worked out in detail by several geologists, most notably 



