relating to the J^ale of the Mississippi. 55 



for, perhaps, twelve hundred years ; carrying the earth by secret 

 paths to a great distance, where it was either appropriated in forming 

 what is now called second bottoms or bluff-flats ; or deposited at a 

 point where it was, at some distant day, to be again removed by a 

 river that did not then exist, and it was destined to assist in laying 

 the foundation of the Mississippi Delta, or what we have called the 

 Orleans basin, with its upper or northern boundary beginning at Ba- 

 ton Rouge and not at Natchez, as supposed by Mr. Dunbar. 



SUBTERRANEAN CAVITIES AND CHANNELS. 



Our first stratum of clay, beneath the vegetable soil, contains a 

 multitude of irregular cavities, traversed by the same clay, and dis- 

 posed like the reticular texture of bones. These cavities are pro- 

 duced and perpetuated by rain water, which, as fast as it is com- 

 pressed by superincumbent weight, passes readily through the soil 

 and vegetable matter, and through this clay, into the next stratum, 

 or it forms small channels between the two. These cavities are 

 lined with a very thin coat of lime or chalk, derived from the rain 

 water, bringing from the surface the spoils of the snail shells which 

 time creates, destroys and decomposes. In very dry seasons, the 

 lime, iron and alumina, give to this stratum of clay, a hardness and 

 adhesiveness almost equal to that of lead. It dries so hastily in the 

 sun, that it cannot be used by the brick-maker. The second stra- 

 tum, which contains a superabundance of sand, requires more alumi- 

 na and iron, to produce the weight and tenacity which are so very 

 important in bricks. It may be doubted whether the levigated marl, 

 mentioned by Mr. Dunbar, which " assumes a compactness and so- 

 lidity resembling pitch," is very well " adapted to the use of the 

 potter." This earth of the Mississippi bottom is alumina, with a 

 considerable quantity of vegetable and animal matter. We have 

 noticed the effects of heat upon this earth, when united with sand 

 and made into brick. While burning, it is extremely difficult to 

 raise and continue the white heat, without producing fusion ; the 

 bricks are very light, friable, and remarkably brittle. 



To show the readiness with which land covered by cane received 

 and absorbed the rain water, we will cite • as instances two tracts 

 thickly set with a natural growth of cane ; both of these tracts 

 received the heaviest falls of rain, without showing the least sign of 

 draining on the surface. The first field contains about eighty acres, 

 and was well knovv'n to the writer before the cane was removed, or 



