Story of the Chautauqua Region 



It is entirely probable that this great conglomerate extended over 

 a considerable portion of the high Chautauqua plateau. Perhaps it 

 has been the cause for the great height of this area, the hard overlying 

 conglomerate protecting the soft shales from rapid denudation. 



The Second Period. Chautauqua Raised Above the Sea 



During the Carboniferous time the entire state of New York, in- 

 cluding its western, Chautauquan end, was slowly raised above the sea, 

 where it has remained ever since. This gradual elevation was asso- 

 ciated with the general uplifting of the Appalachian Mountain system. 

 During the uplift considerable erosion and denudation of the newly 

 exposed land surfaces took place. Then, in the mid-Tertiary period, . 

 there came a very pronounced uplift, which enabled all the rivers of 

 central New York, for example, to cut deep conspicuous valleys. 



The Third Period. The Wearing Away of the Land 



Both during and after the uplift the land was worn away and cut by 

 deep valleys. Any rock strata that may have overlain the Devonian 

 strata have been removed. Over a very large part of New York State 

 the Devonian and older strata are deeply cut by valleys, so that the 

 plateau is conspicuously dissected, particularly near the divides. These 

 valleys are fairly well rounded and matured, but extensive hilly masses 

 remain between them, showing that but a mere beginning has been 

 made toward the removal of the Devonian and older rocks. 



This great dissected plateau slopes southward, thus exposing the out- 

 crop edges of its strata toward the north. The hard upper rock layers 

 protected the soft under ones, just as in the case of the Panama con- 

 glomerate; but as these were undermined, the hard strata were cut 

 back in the direction of the dip, that is, toward the south, and always 

 with a tendency to maintain an elevated position. The hard Helder- 

 berg limestone and its outcrop has in this way produced the great 

 " escarpment " between Mayville and Westfield. 



The Fourth Period. The Glacial Invasions During the Ice Age 



The Glacial Period succeeded the Tertiary uplift and practically the 

 entire state of New York, like many other regions in the northern 

 United States, was covered with a thick sheet of ice. The Chautauqua 

 region is but a small portion of the great district covered by glaciers 

 during the Ice Age. 



When these ice sheets finally retreated, many changes were evident. 

 Over the surface was strewn a sheet of glacial deposits of variable thick- 

 ness. Some of the hills were planed down and rounded, others were 



103 , 



