340 C. W. HALL — KEWEENAWAN AREA OF EASTERN MINNESOTA 



To the north and west of these sharply tilted rocks the Cambrian sand- 

 stones are, wherever seen, badly broken and inclined a.way from the 

 faulted contact with the Keweenawan. 



8. The formation of the fault line in its present attitude was a long 

 continued process. The line of weakness and a succession of fissure 

 eruptions is evidenced by the lava flows themselves. This is Keweena- 

 wan time. The crushing of the sandstones and their upturning is cer- 

 tainly post-Cambrian. The faults in Paleozoic rocks and the displace- 

 ment of Trenton limestones between Minneapolis and Stillwater points 

 to a continuation of the movement of displacement into the Ordovician. 



