334 Tertiary. 



Commencing in the lower tier of counties in the State of New York 

 where the hills are from 600 to 800 feet above the level of the narrow 

 valleys, as they occur in Cattaraugus, Alleghany, Steuben and Chemung 

 counties, and extending South over all the highlands of Pennsylvania, 

 and over Virginia, West Virginia, the Carolinas, and the eastern 

 parts of Kentucky and Tennessee, and South to the Gulf of Mexico, 

 we have an absolutely driftless area; an area of dry land when the 

 marine clays and sands were strewn over the territory adjacent to the 

 Gulf of St. Lawrence, and over the New England States; and also an 

 area of dry land during the period of the drift, of the central part of 

 the continent, and for untold geological ages antecedent thereto. The 

 elevated hills, precipitous ledges, profound valleys, overhanging rocks, 

 and castellated outliers of the Carboniferous conglomerate in Cat- 

 taraugus county, some of which are illustrated in the Geology of 

 McKean county, in the Report of Progress E. of the Second Geological 

 Survey of Pennsylvania, under the name of the Olean conglomerate at 

 Rock City, furnish the most incontestible evidence of the ordinar}' 

 eroding agents through a period of time, commencing long anterior to 

 the Tertiary epoch, and equally as conclusive evidence that no glacier 

 ever passed over that territory. 



During the ages that elapsed from the Carboniferous to the Tertiary, 

 the Ohio river and its tributaries were excavating their valleys, and so 

 also were the streams that flowed through the channel, that drained the 

 northern and central part of the continent, which is now represented 

 by the chain of great lakes. Where the valleys thus ei'oded remain 

 unaffected by the drift, they are frequently immense chasms. The 

 streams which flowed from the divide into the great drainage system 

 of the north, cut out the valleys precisely as did the tributaries flow- 

 ing south or east into the Ohio, and to equally as great depth. Could 

 we see northern Ohio stripped of the drift, we would see a country 

 quite as rough and rugged as southeastern Ohio. But there came a 

 time when this drainage system of the north was obstructed in the 

 region of Lake Ontario, and the waters were thrown back over the 

 country, forming an immense lake. From this lake, deposits of clay, 

 sand and gravel were precipitated over the country overflowed, and 

 from the northern shore or sides of the Laurentian mountains, the shore 

 ice transported to the south bowlders and rocky masses, in the same 

 manner that it transports them now from one side of Lake Winnipeg 

 to the other, and thus, much of the country was changed from its broken 

 and hilly aspect into nearly a level plain. And when this lake over- 



