162 



GEOLOGICAL SURVEY OF ALABAMA. 



From Browns Ferry to the mouth of Elk River the fall is 26 feet 

 in 11 miles. This is known as Elk River Shoals. Its most precipi- 

 tous part is at the' lower end, where there is a fall of 16.5 feet in 

 about 4 miles. 



From the mouth of Elk River to the head of Muscle Shoals, a 

 distance of 5 miles, there is a fall of only 2 feet. 



From the head of Muscle Shoals to Bainbridge th e fall is 85 

 feet in 17 miles, and is known as Big Muscle Shoals 



From Bainbridge to Florence the fall is 23 feet in 7 miles, and 

 is known as Little Muscle Shoals. 



From Florence to the head of the Colbert Shoals the fall is 3 feet 

 in 11 miles. 



From the head of the Colbert Shoals to Waterloo the fall is 21 

 feet in 6 miles. 



Fig. 17. Map showing shoals in Tennessee River, near Florence, Ala. 



The total fall from Browns Ferry to Waterloo is, therefore, 

 1 60 feet in a distance of 57 miles. Sixteen miles of the distance, 

 howeer, has a fall of only 5 feet, leaving a fall of 155 feet in the 

 41 miles that cover the four shoals mentioned. The shoals are 

 really more precipitous than the foregoing figures would indi- 

 cate. For instance, 84.6 feet of the fall at Big Muscle Shoals 

 is in a distance of 14 miles. 



The bed rock at Elk River Shoals is Carboniferous limestone ; 

 that of Muscle Shoals is a hard silicons rock of dark color and 

 flinty structure. 



The following is a statement of the minimum discharge of 

 Tennessee River at Chattanooga : 



*The numbers 5 to 30 at bottom of cut represent miles. 



