This alluvial formation thus produced, will be of 

 two kinds ; the first diffused, and the second circum- 

 scribed, or limited. The first depends on the unin- 

 terrupted flow of the current of any river into a lake, 

 bay, or sea. The second depends on the obstruction 

 or check, which the current of a river may experience, 

 (and which may be saturated with alluvions matter,) 

 by the tide flowing in direct opposition to such current. 



As both these kinds occur, I shall take notice of 

 each, in order to avoid any suspicion of having been 

 partial in my view of the subject 



The river Thames, (or by some called Norwich 

 river,) in Connecticut, is formed by two principal 

 branches, the largest of which takes its rise near the 

 Massachusetts line. In their courses, they receive a 

 gieat many auxiliary streams, all running through a 

 country generally cultivated ; consequently much bro- 

 ken up, and liable to be carried away by rains and the 

 melting of snows ; yet no visible increase of alluvial 

 formation is produced by this river, particularly, as 

 has been observed, on the east side, at its con- 

 tinence with Long Island Sound. 



In this latitude and longitude, the flood tide sets in 

 so strong, and rises so high, that the moment in which 

 it overpowers the current of the river so as to check its 

 descent, that moment the sand and gross silicious mat- 

 ter, which is kept afloat by the current only, is depo- 

 sited at the bottom, or in part wafted back by the tide 

 as far as it sets up. Hence, the principal cause of the 

 bar in that river, which obstructs the navigation above 



