AMERICAN GEOLOGY MACLUREAN ERA, 1785-1819. 219 



with the rest of the globe. The natural line of separation between the 

 two main divisions was that formed by the Allegheny Mountains, 

 which, from the poorness of the soil and the difficulty of access to 

 market, he regarded as probably the last portion of the continent to 

 become thickly inhabited. 



To the west of this range was the Mississippi basin, which, in his 

 view, was destined, on account of climate and soil, to become a coun- 

 try of immense agricultural capabilities. Traversed by only one great 

 liver, which is practically inaccessible to large ships of war, this sec- 

 tion, inclosed b} T the Alleghenies on the east, the Rockies on the west, 

 and the Lakes at the north, he felt to be guarded against invasion by the 

 comparative weakness of their mountain neighbors and the impossi- 

 bility of attack by sea. It would therefore be given over to a nation 

 of agriculturalists, the rulers of which would by nature be deprived of 

 even an excuse for keeping either a fleet or army such as had in the 

 past always brought about the ruin of free and equal representative 

 governments. 



He wrote: 



On this earth or in the page of history it is probable no place can be found of the 

 same extent so well calculated to perpetuate a free and equal representative govern- 

 ment as the basin of the Mississippi, both from its physical advantages and the 

 political constitutions on which the state of society is bottomed. 



The people of the Atlantic slope, he felt, would, however, labor 

 under entirely different conditions. Placed on an extensive coast, 

 accessible at all points, with numerous rivers, they were liable to the 

 depredations of a superior fleet and would naturally become a military 

 people and involved in wars with European nations. 



Maclure's observations, as already noted, were made in almost every 

 State and Territory in the Union, from the river St. Lawrence to the 

 Gulf of Mexico, and the memoir which embraces the accumulated 

 facts was submitted to the American Philosophical Society and printed 

 in their Transactions in 1809. The map of this issue is interesting 

 not alone for its geological coloring, but as showing the paucity of 

 knowledge regarding the physical features of the continent. (See Plate 

 1.) Thus, a continuous range of mountains was figured as extending 

 from northern Maine, along its western boundary, through eastern 

 Vermont, western Massachusetts, across southeast New York and New 

 Jersey to Pennsylvania. More or less parallel ranges were figured as 

 extending down into northern Georgia, two of which turn toward the 

 west, the more northerly of these terminating on the Ohio River just 

 east of the Tennessee, and the other forming the divide between the 

 Tennessee and the headwaters of the Tombigbee River. This last 

 feature was, however, dropped out of the second issue, published 

 in 1817. 



