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.
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 embankment 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 an 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 authentic 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 December, 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 snowstorm; 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 mischief, until the winter of 1816, when it began to be generally fatal to the horses of travellers. So far as I recollect, it was stated, that from thirty to forty travelling horses were destroyed during this winter. The consequences were alarming. In the wilderness, where a man's horse is his chief dependence, the traveller was surprised and distressed to see the beast sicken and die in convulsions, sometimes within three hours after encountering this little insect. Or if the animal were fortunate enough to live, a sickness followed, commonly attended with the sudden and entire shedding of the hair, which rendered the brute unfit for use. Unwilling to believe that effects so dreadful could be produced by a cause apparently trifling, travellers began to suspect that the Indians, or others, of whom they obtained food for their horses, had, for some base and selfish end, mingled poison with it. The greatest precaution was observed. They refused to stop at any house on the way, and carried, for the distance of forty or fifty miles, their own provision; but after all suffered the same calamities. This excited a serious inquiry into the true cause of their distress. The fly, which has been mentioned, was known to be a most singular insect, and peculiarly troublesome to horses. At length it was admitted by all, that the cause of the evils complained of could be no other than this insect. Other precautions have since been observed, particularly that of riding over the road infested with it in the night; and now it happens that comparatively few horses are destroyed. I am unable to describe it from my own observation. I passed over the same road in April last, only two weeks after it disappeared, and was obliged to take the description from others. Its colour is a dark brown; it has an elongated head, with a small and sharp proboscis; and is in size between the gnat and musqueto. When it alights upon a horse, it darts through the hair, much like a gnat, and never quits its hold until removed by force. When a horse stops to drink, swarms fly about the head, and crowd into the mouth, nostrils, and ears; hence it is supposed the poison is communicated inwardly. Whether this be true or not, the most fatal consequences result. It is singular, that from the time of its first appearance, it has never extended for a greater distance than forty miles, in one direction, and usually, it is confined to fifteen miles. In no other part of the country has it ever been seen. From this fact, it would seem probable that the cause of its existence is local. But what it is, none can tell. After the warm weather commences, it disappears as effectually from human observation, as if it were annihilated. Towards the close of December it springs up all at once into being again, and resumes the work of destruction. A fact, so singular, I could not have ventured to state, without the best evidence of its reality. All the circumstances here related, are familiar to hundreds, and were in almost every man's mouth, when I passed through the country. In addition to this, they were confirmed by the account which I received from Col. John M'Kee, a gentleman of much intelligence and respectability, who is the present agent of the general government for the Choctaw nation. He has consented to obtain specimens of the insect for your examination, when it returns again; and will, I hope, accompany the transmission with a more perfect description than it has been possible for me to communicate.
In concluding this narrative of facts, I should be glad to take a comprehensive view of the whole. The bold features in the geology of the United States, as they are drawn by the Blue Ridge, the Cumberland with its associated mountains, and the Dividing Ridge, deserve to be distinctly and strongly impressed upon the mind. Such is the order and regularity of their arrangement, that they can hardly fail to conduct the attentive observer to important results. What has now been said of them, is but an epitome of the whole. I trust the public will soon read, in the pages of your Journal, a detail more perfect and more interesting. And allow me to suggest, whether, under the auspices of our learned societies, some men of science might not be employed and supported in exploring the country, with the prospect of greatly enlarging the science of our country, and of enriching our Journals and Cabinets of Natural History. Tours of discovery have often been made for other objects, and with success. Our country yields to no other in the variety, or the value of its natural productions. We owe it to ourselves and to the world, to search them out with diligence and without delay.
Somers, (N. Y.) Oct. 1818.