ON THE ROCK-SALT DEPOSIT OF PETIT ANSE: LOUISIANA ROCK-SALT COMPANY. REPORT OF THE AMERICAN BUREAU OF MINES. NEW YORK: AMERICAN BUREAU OF MINES, 44 EXCHANGE PLACE. 1867. ON THE ROCK-SALT DEPOSIT OF PETIT ANSE: LOUISIANA ROCK-SALT COMPANY. REPORT OF THE « AMERICAN BUREAU OF MINES. NEW YORK: AMERICAN BUREAU OF MINES, 44 EXCHANGE PLACE. 1867. 5 53, G3 A (Tw 3 AMERICAN BUREAU OF MINES, No. 44 Exchange Place, New York, January 4, 1867. Messrs. Chas. A. Weed, F. J. Pratt, and Charles P. Chouteau : Gentlemen : We have the honor to hand you the Report of the Bureau on a recent examination of the Rock-Salt Deposit of Petit Anse, conducted by the Board of Experts, to which your inquiries were referred. GEORGE D. H. GILLESPIE, President. GEORGE R. A. RICKETTS, Secretary. Digitized by the Internet Archive in 2016 https://archive.org/details/onrocksaltdeposiOOamer Board op Experts, i American Bureau of Mines, V No. 44 Exchange Place, New York, Bee . 24, 1866. ) G. D. H. Gillespie, Esq., President of the Board of Trustees : Dear Sir : The Board of Experts has the honor to transmit herewith its unani- mous Report: on the Salt Deposit of Petit Anse Island, Louisiana. This Report is based upon the preliminary examination of Mr. C. Elton Buck, of this Board, and the notes of a more detailed investiga- tion by Dr. C. A. Goessmann. Consulting Correspondent of the Bureau, who was charged by the Board with the duty of a personal study of the deposit, and an inquiry into its commercial relations. For the Board of Experts, R. W. RAYMOND, J. P. KIMBALL, Secretary. Vice -President. ON THE SALT DEPOSIT OF PETIT ANSE ISLAND, LOUISIANA. Petit Anse Island is situated in Parish St. Mary, in Louisiana, in Long. 91° 51/ West of Greenwich, and 29° 52' North Latitude, about four miles north of Vermilion Bay, and nine and a half miles, by the present road, south of New Iberia. The distance to the latter point, however, is only about seven miles by air line. The island consists of 2210-48 arpents of upland. An arpent — the old French measurement employed in Louisiana — is about one-seventh less than an acre. Fifteen hundred arpents are at present under cultivation, the re- mainder being woodland, pasture, roads, &c. The island is divided between two owners, Judge D. D. Avery, and Mr. John Hays, the property of the former including 1,380 arpents of the upland, and that of the latter comprising the remainder, 860 arpents. A luxuriant growth of forest trees, consisting of magnolia, live oak, hickory, gum-tree, maple, hackberry, black walnut, and cypress, covers a portion of the island. Of these varieties, cypress is the most abundant, and furnishes the principal building material. The immediate vicinity of the island is occupied by extensive sea marshes and cypress swamps, stretching west and southwest from six to to twenty miles. To the north, for about two miles, the surface is covered with tall sea-grasses and scanty brush ; to the east and southeast, for many miles, the swamps are covered with heavy cypress forests. From the highest point of the island, a hill on Hays’s property, 180 feet above the tide-water level, the eye commands a wide prospect, comprising, on the west, the Vermilion Woods, nearly up to Vermilion ville, Miller’s Island, and a broad sheet of prairie, with dwelling houses, and groves of timber; on the north, the forests of Bayou Teche, as far as Jeaneretts, and the Au Large Prairie ; on the east, the Cypremort Woods ; and on the south, the Gulf of Mexico. 8 The only land communication with the island is a plank road, crossing the Bayou Petit Anse and the marshes to the north for nearly two miles, and continuing as a prairie-road to New Iberia. The plank road is of recent construction, having been built during the late war to accommodate the salt transportation of Petit Anse. The nearly circular form of the island, and a surface configuration varied by hillock, valley, ravine, pond, pasture, forest, and cultivated field, give it a picturesque appearance, in the midst of swamp and prairie. The general trend of the hills is N. N. W., and S. S. E., with which the valleys mainly correspond. This leading configuration has been somewhat modified by the sudden and heavy rains of the Gulf coast, which have not only lowered the height of the hills, and filled up to some extent the val- leys, but also produced, by the action of torrents, new channels and ravines, with their own subordinate topographical features. It is difficult, in par- ticular cases, to distinguish the older from the more recent action. Probably all the present surface features have been affected by the same causes ; although there is evidence that the terrain has been exposed to glacial action, of which more will be saip hereafter. The top soil is an umber-colored sandy loam, generally a foot or more in depth, and underlaid by a subsoil of sand, more or less coarse, fre- quently containing lenticular clay-masses of various size. The agricultural products of Petit Anse are mainly cotton, sugar cane and corn. The fertility of the soil is very great. It is claimed that it produces two to three hogsheads of sugar — 1,400 pounds each— to the acre. Oranges, sweet potatoes, and garden vegetables of every variety, may be cultivated with great success, many kinds yielding annually three crops. Springs are sparingly distributed, and only flow during the rainy seasons. Several attempts have been made to obtain more permanent supplies of water, by sinking wells ; but, as might have been expected, with very limited success ; since the only conditions of supply depend upon surface perco- lation, and the imperfect reservoirs afforded by occasional masses of clay. These sources are, at the best, naturally inadequate; and for long periods they fail entirely. The main supply of fresh water is therefore derived from cisterns, and natural or artificial ponds, in which the rain is collected. The temperature of the island is at no time of the year oppressive. According to data obtained from Judge Avery, the maximum heat is 90°- 95° F. ; and the lowest for many years has been 19° F. ; the average 9 being about 65°-70° F., taking day and night the year round. March and April, the latter part of November, and the first part of December, are the more rainy seasons. The situation of the island near the Gulf coast renders the rains sudden and severe, frequently torrent-like. Other meteorological phenomena of a violent or unusual character are, comparatively speaking, unknown. The only recent instances on record are the partial destruction of a crop by storm in 1856, and a hurricane which visited a neighboring parish in 1862. The families of Messrs. Avery and Hays are at present the only residents of Petit Anse. Of these, the oldest inhabitant is John Hays, a Pennsylvanian by birth, who settled on the island in 1790, at the age of fifteen, and has lived there seventy-six years. He relates that on his arrival he found the island covered with dense forest, and not only uninhabited, but totally without traces of human habitation. The Indians then living in the vicinity were the Attakapas. He invited them repeatedly to join him in hunting the bear, panther, wild-cat, and deer ; but they refused, saying that the spot had once been the scene of a great calamity to their race, and that they had never since visited it. , From the numerous relics which have been discovered in the recently excavated salt-pits, it is evident that this island was inhabited before the period of which we have any historical record. Jesse McCaul, digging for salt springs, many years ago, is said to have found, two feet below the surface, an Indian earthen spoon, and a buckhorn ; also a nearly entire skeleton of a supposed mammoth (portions of which were afterwards sent to the Smithsonian Institution). Numerous arrow-heads of stone, and other Indian remains, have also been discovered from time to time ; and in the recent excavations, pottery and basket-work have been exposed in considerable abundance. The baskets are bag-shaped, and constructed of split wild-cane, quite similar in style and material to the Indian baskets of the present day. Mr. D. M. Avery has found two pots, fitted into each other, one foot in diameter at the top, 9|- inches at the bottom, and 8-9 inches high. The immense quantity of fragments of pottery already found on the island leads to the supposition that it was manufactured on the spot by a resident population ; and, indeed, Mr. Avery found what he considered a furnace, originally built in the side of a ravine. The part remaining, 6 feet long and 6 feet high, indicated an 2 10 oval shape. The front wall and fireplace had been undermined and washed away, and the remainder has now suffered a similar fate, so rapid are the changes produced by pluvial influences in this region. Deductions based upon the juxtaposition or superposition of these bones of extinct species (supposing them to be clearly established as such), relics of human industry, and accumulations of vegetable decay, require much caution, since the locality is, and has evidently always been, subject to great and rapid superficial changes ; and as the material now found in the valley where the salt-pits are located is to a considerable depth the same which formerly covered the hillsides, it is obvious that no conclu- sions as to relative age can be drawn from mere difference of level. The layers now exposed by the pits may be the washings from many different strata, and contain remains of widely varying antiquity. The surface formation along the 1ST. O., Opelousas & Great Western Railroad, from Algiers towards Brashear City, belongs to the Mississippi Delta, consisting of clay bottom lands, frequently overgrown with cypress and live-oak forests. The surface-soil, an intermixture of organic matter with the original deposit, is black and plastic, and from six inches to one foot in depth, and underlaid by a light-colored clay, which is char- acteristic for the whole region. The surface is generally below the level of the Mississippi, and protected by levees; but it rises gradually towards Brashear City, where the banks of the Atchafalaya are some fifteen feet high. This rise continues westward along the Teche, and an interstratification of gravelly soil between the surface and the clay bottom makes its appearance. Along the Bayou Teche, the land is sufficiently elevated to be secure against overflow, and is occupied by numerous sugar plantations. This district is known as the “ Garden of Louisiana.” At New Iberia, the banks of the bayou attain a height of nearly twenty feet. The characteristic delta-clay is found underlying all the lands sur- rounding Petit Anse Island. Being comparatively impermeable to water, it prevents natural drainage, and portions of the prairies between Petit Anse and New Iberia are often overflowed after heavy rains, thus seriously obstructing communication. This evil could be obviated by artificial drainage, but nothing of the kind has ever been attempted. 11 The peculiar features of the formation of Petit Anse Island are : 1. The occurrence of superficial strata entirely different from the delta- clay, preserved, probably, by their elevation, from the general denu- dation of the region. 2. The occurrence of rock-salt as an underlying deposit. These two features will be considered in their order. Petit Anse Island is one of five elevations which occur in a bT.W. — S. E. line, amid the otherwise level delta lands of this district. They are: Dupuy Island, Petit Anse, Weeks Island, Cote Blanche, and Belle Isle. Upon the other four, no explorations have been made to ascertain their geological character. It may be that they are also patches of the same formation preserved on Petit Anse. The surface-soil of Petit Anse, as has been observed, is dark loam. Beneath it occur layers of coarse and fine sand, gravel, and clay in lenticu- lar masses. In some places the sand is cemented by peroxyd of iron, and friable pink sandstone, and arenaceous concretions of peroxyd of iron are frequently observable. These various materials are irregularly stratified, generally in curved lines, as if resulting from the action of currents and eddies. They do not conform to any one definite direction or order, but occur in different succession, and sometimes reversed. In short, they display all the phenomena of deposits subjected to the action of currents, sometimes direct, sometimes obstructed. A reversal of the order of deposition is observable in those localities where more recent denudation and re-deposition might be naturally presumed to have taken place. It is difficult to determine what is the original, and what the modified stratification. The stratigraphical changes have been produced by currents, exposure to weather, and occurrences of tough clay-masses, a single circumstance of such unimportant character being sufficient to set in operation a train of ever increasing change. The heavy rains of the Gulf coast have been of course the principal agents in these later processes. The sand and pebbles are of decided silicious character, and much water-worn. The drift contains no carbonates and no protoxyd of iron, but worn fragments of erratic rocks, silicified wood, and even boulders of 60-70 lbs. weight occur in it. One boulder of porphyritic diorite was observed by Dr. Goessmann, which had been taken from one of the pits on the island. It weighed some 70 lbs. This is probably the most southerly boulder yet discovered in the Mississippi Yalley. Prof. Hilgard has discovered but one other locality south of Yicksburg. 12 All these phenomena of constitution and configuration correspond most closely with the description given by Prof. Hilgard in his Report on the Geology of the State of Mississippi, and in later papers, of the forma- tion to which Prof. Safford, of Tennessee, first gave the name of the Orange Sand. The recognition of the Orange Sand upon Petit Anse is confirmed by Professor Hilgard after an examination of the specimens collected by Dr. Goessmann upon the island. The actual exploration of these strata has been confined to a limited area, within one valley and its branches, at the southeast corner of the island, where the salt-pits are located. In opening these pits, according to the account of the workmen, the material passed through was the same as that exposed on the hillsides, namely, gravel and clay, containing remains of vegetation similar to that of the neighboring marshes ; i.