FARM DEVELOPMENT 



Figure 15. The broader valley of the glacial 

 river where it was cut through the loose till, as 

 above the gorge G-G in Figure 14, during glacial 

 times. A-B, surface of flood water in glacial 

 times. E-F, flood water covering the present val- 

 ley. C-D, present stream bed. 



Falls, made famous by Longfellow's poem, are in a 



stream, Minnehaha creek, which flows from beautiful 



Lake Minnetonka and 

 enters the Mississippi 

 river about one-fourth 

 of the way from the 

 mouth of the Minne- 

 sota river to the Falls 

 of St. Anthony. Min- 

 nehaha Falls did not 



begin to form until the Falls of St. Anthony had 



receded past the mouth of Minnehaha creek, when the 



creek waters began to tumble 



into the deepened bed of the 



Mississippi river. Minnehaha 



Falls, like the Falls of St. An- 



thony, have since then gradu- in Figure ie is shown a 



, , , . tion of a river where the glacial floods 



allv receded, by the Waters cut through limestone and sandstone, 



J . 11 forming the gorge at G-G in Figure 



mining into the very loosely Hno un* 



coherent sandstone from be- 





neath the ledge of limestone, 



CaUSing it tO break Off, thus rsptionecewasnt 



1 most of the flood water during glacial 



Wearing 1 away a gorge nearly a times had passed around the Mgher 



e 3 - MI , , 1 land underlaid with rock, as shown 



fourth OI a mile long, at the in Figure 14. A, water at flood. B, 



. .. .. . water when no flood Is on. 



upper end of which is Min- 



nehaha Falls, the Indian name for laughing water. In 

 Figures 14, 15 and 16 is shown one of the slow but mighty 

 changes wrought by water acting through many cen- 

 turies. There is evidence that the two rivers which now 

 flow together at K formerly had their confluence across 

 the line, F, F, F, at least in flood seasons. The north 

 river gradually cut the soft rock out of its east branch, 

 forming a gorge at G, G, and it no longer flows across 

 F, F, F, even in flood seasons. A very small stream now 

 follows F, F, F, 



