72 Bulletin 1, Biological Society of Washington, 1918. 



Valley passes one of the most strongly marked geologic and 

 cultural boundaries on the face of the earth. * * * It is 

 known to students of modern manufactures as the fall line 

 because along it the rivers descend as abruptly as the land ; 

 and it is even more notable as a line of deflection than as 

 one of declivity in rivers. The great waterways of the Middle 

 Atlantic slope maintain their courses through Appalachian 

 ranges and Piedmont hills alike; but on reaching the coastal 

 lowlands they are turned aside literally by a sand bank 46 

 little higher than their depth, and thence hug the upland 

 margin for scores of miles before finally finding their way 

 into the ocean. So the coastal lowlands are nearly isolated 

 by the tidal bays and river-elbows along their inner margin. 

 Measured along the fall line, the Hudson is barred from the 

 Rappahannock, 300 miles southward, by only 60 miles of 

 land and unnavigable water. This remarkable physiography 

 is now and ever has been reflected in the culture of the 

 region. The pioneer settlers of the country ascended the 

 tidal canals to the falls (p. 233) of the rivers, where they 

 found, sometimes within a mile, clear, fresh water, the 

 game of the hills and woodlands, and the fish and fowl of 

 the estuaries, and, as the population increased, abundant 

 water-power and excellent mill-sites, easy ferriage, and prac- 

 ticable bridge-sites; here the pioneer settlements and vil- 

 lages were located; and across the necks of the inter-estu- 

 arine peninsulas the pioneer routes of travel were extended 

 from settlement to settlement until the entire Atlantic slope 

 was traversed by a grand social and commercial artery 

 stretching from New England to the Gulf States. As the 

 population grew and spread, the settlements, villages, and 

 towns along the line of Nature's selection waxed, and many 

 of them yet retain their early prestige; and the early stage- 

 route has become a great metropolitan railway and tele- 

 graph route connecting North and South as they were con- 

 nected of old in more primitive fashion. And just as these 

 natural conditions influenced the white invader, so, and even 



44 In this connection the effect of the tidal character of streams below 

 fall line, and consequent absence of powerful eroding currents should not 

 be overlooked. 



