Departing from the Hudson Bay, and without re garding the mountain chains or ridges, the table land rises slowly, and between the sources of Sus quehannah and those of the confluents of Lake On tario, one or more valleys exist where the summit level between the Atlantic tides, in Chesapeake Bay, and the surface of Lake Ontario falls under nine hundred feet, but passing the basin of Susquehannah, the mountain table land rises more rapidly, and also more uniformly. With some but partial inter ruptions, the rivers flow, and the mountains lie on a vast inclined plain from the valley of the west. branch of Susquehannah southwestwardly, to where the sources of the Yadkin, Kenhawa, and Watauga branch of Tennessee separate. From the latter point, occupied by Ashe county, North Carolina, the great plain declines in the contrary direction, and if the distance is continued to tide water in Alabama and Tombigbee rivers, the length of de scent in the two plains is very nearly equal.
If we draw a line on a good map along the di viding ridge between the sources of the rivers, we shall by the operation discover the fact, that the mountains in no one instance determine the recipi ent; but, on the contrary, the rivers in most cases rise on plains higher than the bases of the chains, and so far from flowing from, they are discharged through the mountains. The Mohawk, though a confluent of the Atlantic, has nearly the whole of its course to the interior of the Appalachian system. The west branch, and most of the minor confluents of the east branch of Susquehannah rise also within the Appalachian chains. The Potomac rises west ward of the central chain, and a similar remark ap plies to James and Roanoke rivers. Passing the basin of James river, we discover the reverse, as, in a distance of 250 miles from the extreme sources of Roanoke to those of Savannah and Chattahooche rivers, the confluents of Ohio have their most re mote sources in Blue Ridge. The entire force of these remarks will be more distinctly seen under the respective heads of the rivers; but we may re mark in this place, that the relative aspect of the rivers and mountains of the United States, almost enforces the theory, that the latter were formed subsequently, and have been broken at various points by the streams, to the courses of which these great masses of rock formed impediments. By tracing the real line of separation between the con fluents of the two great recipients, the reader will be enabled to more distinctly review the individual basins.
Commencing this river line at the summit level between the valleys of the Mohawk and Oneida, it curves first S.W. and thence W. and N.W. by an elliptic indenting into the basin of Susquehannah, and out of which flow the higher sources of Onon dago or Oswego river. This curve, forming the extreme northern boundary of the basin of Susque hannah, is about 120 miles in length, and affords an other and striking instance of the conformity of the line we are surveying, with the curves of the adjacent recipient, as the curve which separates the basin of Susquehannah from the Valley of Onondago, com plies in its general inflections with the south-eastern shores of Lake Ontario.
Sweeping round the sources of the Tioga branch of Susquehannah, which it separates from those of Genessee, the latter a confluent of Lake Ontario, the river line now inflects to a general southern course 65 miles, to that elevated table land from whence flow northwardly the higher sources of Genessee; north-westward the extreme source of Alleghany, and semicircling round from east to south, and on to west, the numerous fountains of Cowanesque, Pine Creek, Sinnamahoning, and other confluents of Susquehannah. From this plateau the water courses flow in every direction, like radii, from a common centre. From it, the nearest tide water is the mouth of Susquehannah, at a direct distance of 185 miles; but the head of tides round from Albany in the Hudson, including the entire course of the Hudson, the head of tides in Delaware, Schuylkill, and Potomac, all fall within 210 miles, and of course within 25 miles of being equidistant from that great crown which stands at the extreme north-eastern source of the immense basin of the Mississippi and the source of the less extensive, but very interesting basin of Chesapeake. It is also distant 90 miles from the mouth of Cata raugus river into Lake Erie, and 110 from Lake Ontario, at the mouth of Genessee river. The pla teau before us is not, however, a mathematical point: its length from the source of Pine creek to that of Clarion river, a branch of Alleghany, is 35 miles, in a direction from east to west, nearly.
From the sources of Pine creek and Clarion river, for a distance of 70 miles, the dividing ridge of the rivers is, for the first instance from the Mohawk valley, a chain of the Appalachian system, but what renders that chain singularly remarkable, as con nected with the rivers, is, that it is the most north western, and most humble in height, of all the chains of the system to which it appertains. Thus whilst the base of the Chesnut Ridge is the most elevated, a circumstance demonstrated by the course of the streams, the chains rise in elevation, descend ing the river valley towards the Atlantic tides; and so far is the source of the rivers at this place from being regulated by the mountains, that the entire course of Susquehannah is across, and not from, the Appalachian system. If we regard the head of the tides as the real mouth of the Susquehannah, the whole of that stream and its minor branches flow down an inclined plain 200 miles wide, and com mensurate with the breadth of the Appalachian system.