^S6 AGRICULTURAr, MTTSEUM. - 



take place, that at New Orleans, three hundred mile* 

 above the actual moulh of the river a canal lately (hit-- by 

 the Baron de Carondelct, between Lake Pont Char- 

 train and the Mississippi, has brought to light a sijb>ura. 

 iuiiiof black earth, mixed with remains of trees, which 

 have neither had time to be decomposed nor converted 

 into coal The two banks o{ the river arc entirelv com- 

 posed of trunks of trees cemented t<gelher by ri^ud, for 

 a length of upwards of three hundred league- to the 

 licight of twelve or sixteen feet. Jbnce it is. that the 

 vernal inundation which swells the river thirty feet 

 above its ordinary level, and overflows the adjacci.t coun- 

 ti-y, which is lower than the bank, is hindered fiom en- 

 tirely returnincr, and stagnates into immense marshps. 

 These swamps are at preserjta bar to culiuje and popu- 

 lation, though hereafter they mi:y supply the means of 

 inexhaustible fertility/' 



To these observations of Mr. Volney, the correctness 

 of which no one who will take the necessarv pains to 

 investigate, can doubt, we shall add a feu more to shew 

 the other processes of nature, thai contribute to the for- 

 mation of (his region. Tne clay, stone, -sand, ligneous 

 and vegetable substances, that are thus brought down 

 from the heights by the waters, deposit themselves along 

 the bottoms and margins of the rivets, forming shelves, 

 plains and banks. On these bar ks there is an annual 

 growth of aquatic vegetables wiiich periodically d« cay, 

 and thereby add to the surface ; in addition to which, 

 there is an -annual deposit of shells and other marine 

 substances, the increase of which is very great and be- 

 yond computation. Shell fish, at least the most common 

 kmds, require little more than a year to get their full 

 growth, and very soon decay. 'J'hese iorm strata, 

 which are again covered by the sediment of the river, 

 and re-placed by a new growth of shells ; thus is the 

 land continuaMy increased by a slow and gradual process. 

 A\ hen in the lapse of time ti)ese banks irnmergc from be- 

 neath the water and become exposed to the genial rays 

 of the Sun, they arc in a short time covered with her- 



