504 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



Close observation presented these facts: For the distance of twenty or 

 thirty miles back from the Mississippi river, and more than forty miles 

 south of Troy, the surface of the country here and there presents numerous 

 " sand-blows," as they are called by the people of that region. These are 

 mounds of sand, differing in size from a few bushels to many wagon loads, 

 and often only a few rods apart. They are principally in the valleys, but 

 sometimes exteiid to the higher grounds. The sand, in these " blows," is 

 very fine grained and light colored along Obion valley. They increase in 

 size in the direction of the Mississippi river and of these lakes. On the 

 western side of the Eeel-foot Lake, near the former outlet of that river, 

 some of these sand-blows are said to be half the height of a house, even 

 now, when they are all greatly flattened by time; and that places which 

 seem once to have been much lower, have been filled up by them. 



Connected with these sand-blows are numerous fissures or chasms in the 

 earth. These are known to have been produced at the time of the earth- 

 quake; and as they abound in the region of the lakes, and some of them 

 are very large and occur oh hill sides, where the dislocated portions have 

 tumbled off, or slid down, the conclusion drawn by many was that the lakes 

 had been formed by the sinking of the earth. This opinion is sti'engtheued. 

 by the appearance of the extensive forest, before described, miles in length, 

 standing in fifteen feet water. Were this conclusion correct, then these 

 fissures ought to extend entirely around the margin of the lakes, which is 

 not the case; and all the streams emptying into the lakes from their old 

 levels, would have some fall at their mouths. But, instead of falls, there 

 is back-water in all such streams for several miles, and in the Reel-foot 

 "riv^er itself for ten miles. 



The conclusion to which such facts lead, is that these lakes have not been 

 formed by the sinking of their beds, but that the waters have been raised 

 so as to overflow all the grounds of less elevation than fifteen feet above 

 the original level of Reel-foot river; and that this rise was caused by the 

 daunning up of its chanjiel by the sand-blows. 



That these mounds of sand have not been formed by surface currents of 

 water, drifting the sand along the hills and valleys, seems certain, because 

 they are uniformly pure white sand, without any intermixture of clay or 

 leaves, or branches of trees, or gravel, or other surface substances. 



But there is still another fact which more fully demonstrates that Reel- 

 foot Lake has been formed by its channel having been dammed up by 

 the sand-blows. At the foot of the lake, this river, leaving its old channel 

 towards tlie Mississippi, which has become an embankment of sand, starts 

 from the lake with a fall of fifteen feet, carrying it to the ordinary level of 

 the main Mississippi valley. From thence it reaches the Obion River, dis- 

 tant twenty miles, in a divided condition, forming several smaller streams. 

 This fall of fifteen feet, is produced by the passage of the waters of the 

 lake over a depression in tlie dividing ridge, or elevateds grounds, originally 

 midway between the two rivers. When the waters have fallen the fifteen 

 feet, on the southern slope, they reach the roots of the cypress trees, grow- 

 ing in the swamps on the soutli side of the dividing ridge. On the north 

 side, the cypress trees are standing fifteen feet in the water of the lake. 

 This proves tliat the roots of these trees stand in grounds of the same 



