JV'. W. Portion of Lake Huron. ^ 255 



Of the Grand Manitou, which now succeeds, little is 

 known. Its western termination is remarkable for its ma- 

 jestic precipices. 



The northern mainland is high, barren and rocky ; the 

 southern shore, being of a secondary formation, is level, and 

 abounding in marshes and the densest woods. 



The north west portion of Lake Huron, (whose outline 

 has just been traced) in common with the rest of the earth's 

 surface, exhibits many evidences of change and convulsion : 

 when, and in what manner effected, I am not prepared to 

 state ; but they are obvious. 



The original form of the bed of the Lake may be de- 

 scribed as a triangular valley of great extent, divided in an 

 easterly direction by the Manatouhne Ridge into two une- 

 qual parts, the northern being rocky and of variable ele- 

 vation ; and the southern more uniform in its level, and 

 generally lower : in its present form, the bed of the Hu- 

 ron Lake is covered with the debris of distant countries : 

 its rocks are furrowed and abraded ; its loftiest heights over- 

 thrown, (of greenstone, one of the most tenacious of miner- 

 als, as in the narrows of St. Joseph) separating large tracts 

 from the Main ; and finally, passages from ten to twelve 

 miles wide and ten long, are forced in the Great Manitou-- 

 line barrier itself. These violences, and particularly the 

 first and last, iadicate a more general and powerful agency 

 than that of a gradual accumulation of the waters of Lakes 

 Huron and Superior, whose united surplus requires only an 

 outlet of three hundred yards in breadth (R. St. Clair) in 

 place of the four Manitouhne Detours. The effect of a 

 gradual accumulation of water would have been to have fil- 

 led the north division of Lake Huron, and in the end, to 

 have inundated the lower grounds on the south and east by 

 an embouchure at the point of least elevation in the Great 

 Ridge. I am inclined to the opinion that an enormous body 

 of water has rushed over these countries (a " debacle") 

 swept from distant lands, the collossal fragments of rock so 

 frequent in the Lake ; and formed the breaches called the 

 detours ; perhaps at the same time when the passages of the 

 Hudson and Shenandoah were opened, and the heights of 

 Quebec, and the marshes of Montreal were covered with 

 the ruins of annihilated mountains. 



