PAPERS OF GENER-AL INTEREST 35 



the New Madrid earthquake of 1811 was the result of move- 

 ment in some portion of this fault zone. 



The events in the geological history of southern Illinois 

 which have been mentioned and briefly discussed in this ad- 

 dress constitute only a fragment of the complete history of 

 the region. They are, however, the events which are re- 

 corded in the rock strata which are actually exposed in the 

 region. Many hundreds of feet of strata underlie the whole 

 of this portion of the state, beneath the formations which 

 have been considered, but the history which they record i«^ 

 not so easily or so certainly determinable. There is also 

 a long history since the close of Paleozoic time which is full 

 of events of great interest, but neither this more ancient nor 

 the more modern portion of the story can be considered at 

 this time. 



