were buried in consequence of it, and strong fears are entertained by the inhabitants, that the same cause will yet submerge in the Mississippi, the whole of the present landing-place. These facts, I think you will say, furnish satisfactory evidence of the alluvial character of the country at Natchez. The same character belongs to the whole extent south of the Dividing Ridge. This may be safely inferred from the general features of the country. But I have two facts, of a geological kind, to mention, both of which go to confirm the opinion. 1. A well was dug in the Choctaw nation, at the agency of the United States, in the year 1812 or 1813, under the direction of Silas Dinsmore, Esq. the agent. The excavation was continued to the depth of one hundred and seventy-two feet. No water was found. At no great distance from the surface, marine exuviæ were found in abundance. The shells were small, and imbedded in a soft clay, similar to marine earth. This formation continued till the excavation ceased. Dispersed through it, were found lumps of selenite, or foliated gypsum, some of which were half as large as a man's fist. Specimens of the earth, the exuviæ, and the selenite, have been transmitted for your examination. This excavation was made one hundred and twenty miles north northeast of Natchez. The Pearl River is four miles to the east of the place, and is the only considerable stream in this part of the country. 2. In the Chickasaw nation, one hundred and seventy miles north of the Choctaw agency, commence beds of oyster-shells, which continue to be seen at intervals for twelve miles. Four miles from the first bed, you come to what is called "Chickasaw Old Town," where they are observed in great abundance. They are imbedded in low ridges of a white marl. They appear to be of two kinds. Specimens of each, and also of the marl, you have received. "Chickasaw Old Town," is a name now appropriated to a prairie, on a part of which there formerly stood a small village of Chickasaws. The prairie is twenty miles long, and four wide. The shells occur in three places as you cross it, and again, on two contiguous hills to the east of it, at the distance of four miles. They do not cover the surface merely. They form a constituent part of the hills or plains in which they are found. Wherever the earth has been washed so as to produce deep gutters, they are seen in greatest abundance. Nor are they petrifactions, such as are found in rocks. They have the same appearance as common oyster-shells, they lie loose in the earth, and thus indicate a comparatively recent origin. They occur _three hundred miles_ northeast of Natchez, and but _sixty_ miles south of the Dividing Ridge.