172 GEOLOGY OP EASTERN WISCONSIN. 



The average elevation of the rim of the basin above the point where 

 the river leaves the state is about 250 feet, its average distance about 

 50 miles, showing an average fall of about five feet per mile. But 

 this is less to the point than the following. 



The average elevation of fifteen powers, the first of im])ortance on 

 their respective branches is about 153 feet above the surface of the 

 river where it leaves the state at Beloit. The average fall from these 

 powers to the state line is a little less than three feet per mile. 



"With these general statements, we will set aside the tributaries, 

 several of which are important, and consider more accurately the 

 main stream between Horicon and Beloit. The collecting area above 

 Horicon is 436 square miles, upon which the annual rainfall, reckoned 

 at thirty inches, would be 30,387,456,000 cubic feet. Allowing one- 

 half for evaporation, filtration, and other sources of loss, the theoretical 

 discharge at the outlet of Horicon marsh would be 15,193,728,000 

 cubic feet. Reckoned at the lowest rainfall in the last thirty years, 

 the amount would be 10,114,749,120 cubic feet. Col. Worrall gives 

 in the report previously referred to, as the result of a careful meas- 

 urement of the flow at a time when the volume was estimated to be 

 only three-fourths of the average, a supply of 27,651 cubic feet per 

 minute, or 14,533,365,600 cubic feet per annum, from which it would 

 seem that the calculated amount is not far from the truth. From 

 the foregoing data, estimating the accession from tributaries, it is 

 thought to be safe to consider the average flow between Horicon and 

 Beloit as in round numbers 50,000,000,000 cubic feet per annum. 

 The fall from Horicon to the state line is 127 feet. An estimate of 

 the theoretical power generated by the main river shows it to be up- 

 wards of 20,000 horse power. Of the 127 feet fall, less than 60 feet 

 are utilized. Of the unused portion there is more than 30 feet fall 

 between Horicon and Watertown, corresponding to above 1,600 horse 

 power, and about 23 feet fall between Janesville and Beloit, equal to 

 upwards of 7,000 horse power. A portion of this latter may readily 

 be made available at Beloit by means of a race leading from a dam 

 situated above the slack water of the present one. Another power 

 near the state line can also be utilized to the profit of this place. 

 Upon the river and its tributaries are a large number of lakes that 

 may be utilized as storage reservoirs, thus aflecting a much greater 

 economy in the use of the water. 

 Water power of the Fox river .^ The upper Fox river from its 



' Tor the leading facts here given, I am indebted to an article prepared for the Cen- 

 tennial Commission by Pres. G. M. Steele, of Lawrence University. I am also indebted 

 to Prof. J. C. Foye of the same institution for similar favors. 



