THE FRONT OF THE PROCESSION OF LIFE. 85 



dolerite, three or four miles in width, runs like a backbone 

 from the head of Kewenaw Point, southwest and west, to 

 the neighborhood of Ontonagon (see Fig. 30), Upon this 

 the copper mines of the region are located. In each direc- 

 tion from this backbone slopes the sandstone which was 

 upturned by it (Fig. 31). Directly across this adamantine 

 ridge passes a stupendous cleft, which has been filled with 

 water from the lake. Thus has been formed Portage Lake, 

 a narrow, winding bo4y of water, which vessels navigate 

 from the east to within two or three miles of Lake Supe- 

 rior on the west. Commerce has undertaken to complete 

 the work begun by Nature, and soon Kewenaw Point will 

 be an island. 



Toward the eastern extremity of Lake Superior the for- 

 mation reposes in nearly horizontal beds, and the erosion 

 of the lake along the southern shore has carved out bold 

 escarpments which arrest the attention of every traveler. 

 These have been named the "Pictured Rocks" (Fig. 32), 

 from the diversified colorings of the various portions of the 

 sandstone mass. It is a dangerous coast, and no species 

 of craft ventures within inspection distance except in calm 

 and settled weather. The high bold wall looks sheer across 

 the lake, and the storm-wind rolls tremendous surges 

 against its stern, defiant face. They have excavated cav- 

 erns which a canoe may traverse, and in which the impris- 

 oned billows howl with the resonance of a Nahant purga- 

 tory. They have carved out mimic architecture and spread 

 a mimic sail. In times long gone by they have flanked a 

 stubborn bluff, and cut it off from the main land by a mili- 

 tary " ditch" of the most successful kind, since it is a mile 

 w T ide, and is navigated by the largest vessels. The isolated 

 piece is known as Grand Island. 



" The range of cliffs to which the name of Pictured Rocks 

 has been given," say Foster and Whitney, " may be regard- 



