226 matured /BMracles, 



it strikes a water level, and there it will build 

 out a terrace near the level of the water sur- 

 face. The width of these terraces will be de- 

 termined by the time the water has stood at 

 that level and the extent and nature of the 

 soil from which the debris comes. The evi- 

 dences that are cited, pro and con, would fill a 

 small volume, but it is sufficient to say here 

 that the sum of the evidence goes to show that 

 there was an ice dam formed at a point near 

 Cincinnati and that it was maintained for a 

 considerable period of time. Terraces were 

 formed running up the Ohio and its tribu- 

 taries corresponding to the level that the water 

 must have risen to if the valley were filled up 

 with ice. These facts, taken with the greater 

 fact that the ice sheet actually did cross the 

 Ohio Valley into Kentucky, as is shown by the 

 terminal moraine, seems to prove conclusively 

 the existence of such a lake during the period 

 that the ice rested at its extreme limit. The 

 fact that in some places successive terraces are 

 found does not disprove the theory, because it 

 is more than likely that when the ice receded 

 it did so in successive stages, remaining at dif- 

 ferent positions for a considerable length of 

 time. There is abundant proof of this in the 

 successive moraines and also in the formation 

 of successive terraces. Some of these terraces 

 could have been formed from other causes. 

 It does not require any great stretch of the 



