BUFFALO SOCIETY OF NATURAL SCIENCES 65 



Wiscoy Shale. 



Lying above the Nunda sandstone in the Genesee Valley is 

 a mass of shale named after the exposure in Wiscoy creek. 

 This is limited definitely below by the heavy Nunda sand- 

 stone. In Erie county the Laona sandstone is indefinite. 

 Above its probable horizon and therefore in the horizon of the 

 Wiscoy are shales similar in all ways to the Gardeau. So much 

 do the shales and sandstones of these three formations merge that 

 no lines of demarcation are to be distinguished. 



The shale lying above the possible Laona sandstone can be 

 seen in the heads of the gullies east of Holland and above 

 Johnson's Falls north of Strykersville. The shales outcropping 

 at the south eastern corner of the county in the headwaters of 

 Cattaraugus creek must belong to this formation. They can be 

 seen at Yorkshire Center. 



Post-Portage History of Erie County. 



For Erie county the time following the close of Portage time 

 was a period of slow upheaval. Whether our rocks were above 

 the sea at the time of the deposition of the Chemung rocks can 

 not be said. They probably were above water during the 

 Carboniferous in common with the formations to the southward. 

 The mountain making which marked the end of the Paleozoic 

 seems to have affected them but little, though their permanent 

 emergence above the sea probably occured at that time. Of the 

 life that must have flourished on this new born land we have no 

 record. 



The time following the emergence of the land from the sea 

 has been a time of destruction. The various agencies of sub- 

 aerial erosion began their attack upon its newly emerged rocks. 

 Waves beat upon its edges. Frost and rain rent asunder and 

 dissolved the rocks. Streams began their appointed work of 

 degrading the new land to the level of the sea. But of this 

 erosion we have little record. Some of the valleys now occupied 

 by our streams were undoubtedly eaten out by the rivers of that 

 time. The topography of the county has changed materially 

 since, yet its main features exist now as they existed then. The 

 valley of the Cattaraugus was eroded prior to the advance of the 

 great ice sheet. Tonawanda creek was also entrenched in its 



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