CHAPTER III. 



SEQUENCE OF GEOLOGICAL EVENTS. 



Let us picture to ourselves the succession of the geological 

 events which occurred in this region since Lower Devonian 

 times. 



The Lower Devonian in this part of the country was a 

 limestone making age, when the pure, and presumably warm 

 waters of the great interior Palaeozoic sea, which stretched 

 from the Adirondacks to the Rocky Mountains, was in- 

 habited by corals, crinoids, and other pure water animals. 

 Miles upon miles of coral reefs stretched across what is now 

 the State of New York, and westward to the Mississippi 

 River, and beyond. All that portion of the "vast American 

 Mediterranean Sea," as Dana has called it, was inhabited by 

 myriads of coral-building polyps, which constructed a reef, 

 comparable to the Great Barrier Reef of Australia. This 

 ancient reef was a barrier reef for the Devonian continent of 

 North America, which lay to the north, and which consisted 

 of the old Archaean lands, with the additions made during 

 Cambrian, Ordovician and Silurian times. 



This ancient coral reef now constitutes the Corniferous 

 limestone, which can be traced from Buffalo eastward 

 nearly to the Hudson River, and westward into Missouri 

 and Iowa, with a northern spur running up into the penin- 

 sula of Michigan. Northern Illinois and Wisconsin, at that 

 time, seem to have been above water. (Dana). Similar coral 

 reefs were forming in the seas w T hich covered portions of 

 New England and Canada. 



Dull-colored and unattractive as these ancient coral reefs 

 may seem to-day to the ordinary observer, they nevertheless 

 had beauty once, beauty comparable, if not superior, to that 



