108 



The same reasoning will hold good with respect to 

 the deposites of vegetable exuviae in various parts of 

 the United States ; for in not one instance, can I find 

 that vegetable remains have been discovered lying be- 

 tween a certain specified depth, (which is, on an ave- 

 rage, upon the margin of the alluvial district, from 

 thirty-five to forty feet,) and the surface of the ground. 



This being the case, all ideas of our alluvial dis- 

 tricts having been formed by deposites from an annual, 

 or, (which sometimes happens,) semi-annual inunda- 

 tion of the lands by our rivers, is at an end, and for 

 reasons already advanced. 



A very different opinion prevails with many I know; 

 and among a host of others, is Mr. Stoddard, who in his 

 interesting sketches, when speaking of the Mississip- 

 pi, observes " The banks of the river are composed 

 of alluvious strata, and in places where they newly 

 cave in, the different layers are easily distinguished. 

 The banks between the Ohio and Missouri, have gene- 

 rally, in a low state of the water, an elevation of more 

 than forty feet, and exhibit to the eye about nine hun- 

 dred distinct layers. What conclusion results from 

 this fact? Most certainly, that these alluvions banks 

 have been accumulating during a period of nine hun- 

 dred years ; and probably much longer, as the freshes 

 since the first discovery of the country, have not risen 

 over them, more than once in twenty years. No doubt 

 the number of layers is precisely the same as that of 

 the freshes."* 



* Stoddard's Sketches, page 383. 



