1 84 Dr. BiGSBY on the Geography and Geology of Lake Huron. 



pands into basins, but is usually very narrow. About three miles to the west 

 of Muddy Lake, it is not more than | of a mile broad, and has six or seven 

 islets crowded in it. It is very shallow. 



Muddy Lake, bounding the south-west side of St. Joseph, is a fine sheet of 

 water, of irregular shape, 17 miles long-, and varying from 2 to 7 in 

 breadth. It has received its name from the nature of its bottom. There is 

 one small isle at the upper end, and a large one called Isle a la Crosse at the 

 bottom, with two or three others. Its shores are deep embayments ending in 

 grassy marshes, especially on the south-east side. There are several shoals ; 

 one, having Q^ feet water, at the foot of the Middle Passage ; another some- 

 what to the south-west, and some dry rocks at the lower end of the lake. 

 Sugar Island and George Island, the former 20, the latter 12 miles long, are 

 the two principal islands west of St. Joseph in the water communication be- 

 tween Lake Huron and Lake Superior. The lower end of Sugar Island con- 

 stitutes the northern shore of Muddy Lake ; that of George Island terminates 

 in the Middle Nibish, and the north-west Nibish rapids. 



The Nibish rapids, which are 4 miles long, or more, are separated from one 

 another by these two islands. The lesser or south-western rapid has been 

 already noticed as flowing between Sugar Island and the southern main. The 

 middle Nibish, distant one mile from the north-western point of St, Joseph, 

 divides George Island from Sugar Island, and empties itself principally 

 through the middle passage. The waters of the north-west and north or 

 Little Nibish pass off" on the northern side of St. Joseph by two basins of com- 

 paratively calm water, 3 and 5 miles long respectively, divided by an im- 

 perfect barrier of islands ; the lower basin discharging into the Narrows of 

 Pelletau. 



The Nibish rapids terminate upwards in a large basin, 8 miles long, and 10 

 or 12 broad, called Lake George, containing, besides the upper portions of 

 Sugar and George Islands, a multitude of smaller ones. 



The Straits of St. Mary, which unite Lake George to Lake Superior, are 

 17 miles long, and from | to ^ of a mile broad, and have very violent rapids at 

 a narrow marshy spot about 2 miles above Lake George. 



The Michilimackinac, or south-west arm of Lake Huron, has never been 

 examined, or only by the military engineers of the United States, whose 

 labours have not hitherto been communicated to the public. It is connected 

 with Lake Michigan by the strait of Michilimackinac, from 8 to 1 1 miles 

 wide, and of insignificant length, as being formed only by two opposite pro- 

 montories. 



Its south side presents no peculiarities, except a peninsula, called False 



