3^8 Geology, ^c. of Tennessee, ^c. 



If the country north of Natchez is alluvial, no one will doubt 

 it is so from this place to the Gulf of Mexico. At Baton 

 Rouge, one hundred and forty miles north of New Orleans, you 

 meet the first elevated land in ascending from the gulf. The 

 banks of the Mississippi are higher than the interior, and would 

 be annually overflowed by the river, but for a narrow embank- 

 ment of earth about six feet high, called the Levee. By 

 means of this, a narrow strip of land, from half a mile to a 

 mile in width, is redeemed, and cultivated with cotton and the 

 sugar cane, to the great advantage of the planter. Generally, 

 within one mile from the river, there is an impenetrable 

 morass. The country has every where the appearance of aa 

 origin comparatively recent. Not a rock on which you can 

 stand, and no mountain to gladden the eye ; you seem to have 

 left the older parts of creation to witness the encroachments 

 which the earth is continually making upon the empire of the 

 sea ; and on arriving at the mouth of the Mississippi, you find 

 the grand instruments of nature in active operation, producing 

 with slow, but certain gradations, the same results. 



A destructive Insect. 



But I will not enlarge on a fact already familiar. I will ask 

 your further indulgence only, while I communicate an authen- 

 tic and curious fact for the information of the zoologist. 



In the Choctaw country, one hundred and thirty miles 

 northeast of Natchez, a part of the public road is rendered 

 famous on account of the periodical return of a poisonous and 

 destructive fly. Contrary to the custom of other insects, it 

 always appears when the cold weather commences in Decem- 

 ber, and as invariably disappears on the approach of warm 

 weather, which is about the first of April. It is said to have 

 been remarked first in the winter of 1807, during a snow- 

 storm ; when its effects upon cattle and horses were observed 

 to be similar to those of the gnat and musqueto, in summer, 

 except that they were more severe. It continued to return 

 at the same season of the year, without producing extensive 



