WATER-POWERS OF ALABAMA. 9 



in a northwesterly direction to Tuscaloosa, thence in a northerly 

 direction to a point near Tuscumbia, and thence northwesterly 

 to the Mississippi line. 



The southwestern boundary of the Cretaceous passes from 

 Fort Gaines, approximately, through Clayton, Troy, Snow Hill, 

 and Livingston, in a northwesterly direction. 



It may be said in a general way that the streams have their 

 greatest falls in passing from an older to a younger geological 

 formation. Tallassee Falls, on the Tallapoosa, and Wetumpka 

 Falls, on the Coosa, are made in passing from the Crystalline to 

 the Cretaceous. Those on Talladega Creek and other small, 

 streams in entering the Coosa Valley from the southeast in 

 Talladega, Calhoun, and Cleburne counties, are from the Crys- 

 talline to the Paleozoic. The shoals above Centerville, on the 

 Cahaba, above Tuscaloosa, on the Black Warrior, and near 

 Tuscumbia, on the Tennessee River, are made in passing from 

 the Paleozoic to the Cretaceous. As the Coosa River runs off of 

 the Paleozoic on to the Crystalline near Talladega Springs, the 

 shoals above this point reverse the general order by being made 

 in passing from a younger to an older formation. 



STREAMS AND WATER POWERS. 



The following is a statement, according to water shed, of 

 the important streams and such data concerning thehi as can be 

 compiled from the work of the Alabama Geological Survey, the 

 United States Weather Bureau, and the United States Engi- 

 neering Corps, combined with the hydrographic investigations 

 of the United States Geological Survey under the direction of 

 the compiler of this report. Aside from certain surveys made 

 to obtain maps and profiles of Tallapoosa River and Big Sandy 

 Creek, the work done by the Hydrographic Division of the 

 United States Geological Survey in this State deals exclusively 

 with the amount of water flowing in the streams, and is in- 

 tended to give a safe basis for calculation of lowi water volumes 

 at all seasons of the year, and for several consecutive years, in 

 order to arrive at their value for water power, irrigation, muni- 

 cipal supply, mining, navigation, etc. In .order to do this cer- 

 tain convenient stations have been established on important 

 rivers. At each of these stations a gage rod is set to show the 

 fluctuations of the streams ; and a gage reader is employed to 

 observe the height of the water every morning at the same hour, 



