ture, that all the laws of physics are recurred to for pur-longing to them, would be of great value. How much, then, does it concern the interests of the United States, that rational estimates of the national resources, with all those infallible indications which should precede internal improvements, and whatever else appertains to a monument of such singular importance to them as a general geological map would be, should be done with the utmost accuracy? It seems called for both by the best interests and the reputation of the country. The mineralogical branch is composed of men who, keeping up with the knowledge of the other branches, have devoted themselves rather to a practical study of that portion of the geological series which comprehends the metalliferous rocks, and the other productive branches. In England, the demand for useful information from this class is so great, that the profession of mineral surveyor has grown out of it, one entirely unknown at present in this country.* In estimating the value of an estate there, the capacity of the agricultural surface is not alone considered, but a great importance is given to the probable perpendicular value of every acre, as it can be computed upon geological principles. The value of an estate to an individual depending very much upon these circumstances, men of long experience and approved judgment are alone confided in. If this, as it must be seen to be, is of so much consequence to individuals, of what immense importance is it not to the State Governments, in putting their enactments into operation, to select individuals of the greatest experience? For how is that complex appearance of rocks in different parts of the same country, which, though altogether different in their external characters, may be true equivalents of each other, to be reconciled by men who have only studied them in books? or how can men claim to have their opinions confided in respecting the tendency, direction, and quality of metalliferous veins, or the probable existence of coal measures, upon which the outlay of great capitals depends, who have never been down in a mine, and have studied minerals only from cabinet specimens ? In geology no learning can supply the place of experience. A geologist may be an indifferent analyst, but certainly no man should be presumed a geologist merely because he is a learned chemist or a profound mathematician. Such an important trust, therefore, as is comprehended in the geo logical survey of a State, should be confided only to men of long-approved experience. I have thought these observations not out of place, because, in the incipient encouragement now given to geology by some of the State Governments, and which will probably be done by all of them, it is important that the few individuals in the country who have the requisite experience, should not be overlooked in favor of others, who are perhaps not aware themselves of the extent of practical experience required to make any man's labors valuable, and worthy of being transferred to geological maps of the countries they survey. It must be evident that a geological map of any country, upon which all the important mineral and metallic deposites should be accurately laid down, with their direction, extent, and other important incidents be Mr. William Smith, who has received the first Woolaston gold medal from the Geological Society of London, was a mineral surveyor, and the author of the first geological map of England. Before I close this descriptive portion of my report, I shall ask to present a few remarks on the Arkansas and Red rivers, which I trust will be found somewhat interesting. Both these streams are remarkable for their tortuous and serpentine course, and for the important deflections from their courses, which can be sometimes traced. The history of Red river illustrates well movements of this latter class. From the point where it turns to the east, a little north of 31° north latitude, it appears to have once flowed in a south direction down the line of the Atchafalaya, into the bay bearing that name, in the Gulf of Mexico. There is a chain of lagoons on that line still rafted up with timber, and no doubt, when a head was formed capable of resisting the current, it gave the river its present easterly direction into the Mississippi. In those remote periods when the False Washita and the other tributaries of Red River were working out its channel, the deposites of timber must have been immense, not only filling its channel to the Gulf of Mexico, as I have supposed, but rafting up its present channel as low down as its present mouth in the Mississippi. The remains of those ancient rafts are still to be seen near its mouth, adhering to its banks, the main body having rotted away, and passed down with the current, to the point where the operations commenced of clearing out the present raft. But even now, such is the abrasion produced by the river, that the annual accumulation of timber at the head of the great raft is very great, and the consequent inundations from back water very injurious. When the great work of cutting the raft out is accomplished, an immense quantity of rich lands will be brought to their true value, and the salubrity of the country much improved.* These chains of lagoons are found both on the north and south sides of Red river, and are amongst the immediate causes of the insalubrity of the climate during certain months. The past summer was intensely hot and dry, and one of these large lagoons, near Lost Prairie, on the Mexican side of Red river, a beautiful tract of land over which I passed, had experienced so much evaporation that it could not preserve its fish; the water became glairy, and incapable of sustaining them, and they were floating dead on the surface. The course of the Arkansas is, in like manner, subject to constant change, as a small circumstance will lead to the deflection of this noble, but too uncertain stream. The lodgment of a tree will be the commencement of a bar that will throw the current to the other side, which, beating against a low and weak part of the opposite alluvial bank, *When Captain Shreve, so much distinguished for his skill and dil gence in removing this raft, came upon the ground in the spring of 1833, he found it dead water in Red river for forty miles below the timbers which formed the raft, and which then extended up the river for at least one hundred and fifty miles. About one third of the sur face of the river was occupied with dead timbers, and numerous nud islands had been formed, on which trees and bushes were growing. There were a great many bayous and low places, by which the water of the river was led to various lagoons and swamps, once the ancient and, confining the stream to its old channel, produced a current of bed of the river; these he stopped up with timber taken from the raft, three miles an hour. The general depth of the river was twenty five feet, but in other parts where mud banks existed, the depth was only fifteen. As soon as the raft was sufficiently cut out to restore a good current, these were swept away, and an average depth of twenty-five feet produced. During the first season he succeeded in removing about seventy miles, and there is every reason to believe that in the course of 1835 Captain Shreve will have opened a good steamboat navigation the entire length of the raft Geological Reconnoissance. will, in a short time, if the bank happens to form a reach there, wear its way through, leaving an island and a chain of lagoons in its old bed. In the vicinity of the Mammelle mountain is an immense swamp, through part of which I passed, and which contains, perhaps, thirty thousand acres. The timber on each side, being much killed by the water, stands dead in innumerable lofty bare masts, forming a picture of perfect desolation. The cypress, the cottonwood poplar, and the populus monilifera, the hackberry, the triple-thorned acacia, § and many other trees, attain an immense size here. The lagoons in this swamp extend for several miles where the old bed of the river was; wild geese, ducks, and other aquatic birds, are here in incredible numbers, as well as swans occasionally. Nothing can be more singular than the aspect of the trees in this wild place. Their trunks appeared to be painted red for about fifteen feet from the ground; at that height a perfectly level red line extended through the whole forest, marking the rise of the waters at the last great inundation, which occurred in June, 1833, when the Arkansas rose thirty feet. Millions of acres of rich bottom land of these countries are thus rendered useless, and can never be brought to their intrinsic value but by levées, constructed at particular points, to keep out the waters from the direct course of the river, and the back waters of the bayous that empty into the river. Until measures of this kind are taken, these districts will be a nuisance to the settlers, both in respect of their insalubrity, and their being the resort of the numerous gangs of wolves which infest the country. I spent one night in the swamp alluded to, that of the 22d November last. The thermometer had fallen to 24° Fahrenheit, and strong ice was making. The noise made by the incessant howling and yelling of these animals exceeded any thing I had ever heard, some barking in one tone, some screaming in another, as if each was suffering bodily pain. This uproar is generally loudest just before the approach of day, and appears intended as a signal for stragglers to come into the wilderness, where they usually crouch during the day. From this point of the river down to its mouth, a distance of about three hundred miles, a fine opportunity presents itself of studying not only the structure of this vast body of rich alluvial land, but of the action of the river, and I passed a week in following it to its junction with the Mississippi, landing, and examining the country at many interesting points. The whole line presents a succession of reaches, sand bars, and mutations, produced in the manner I have before mentioned, and the serpentine course thus established doubles the distance. Its general course to the Mississippi is southeast, but it is constantly, every five or six miles, describing curves, and following the direction of southwest and northeast. The channel is thus alternately on the right and left bank of the river. Sometimes an extensive sandy beach will project itself from the opposite shore, and just so far into the channel as to render it very difficult to get over with a boat drawing three feet. These beaches sometimes cover more than fifty acres of land, and are thrown up by the stream as it abrades the banks at the foot of which it runs. The banks being thus constantly undermined by the action of the river, immense masses of timber, together with the lofty canes, twenty to twenty-five feet high, that grow up with it, fall into the river with the earth about their roots, and thus at the same time form the snags and sawyers which embarrass the stream, and a point of resistance which gives a new direction to it. [25th CoNG. 1st SESS. Sometimes, during the great freshets which descend from the upper country, the river not only breaks through the reaches of land which jut out into the river, but absolutely gets under the extensive sand beaches, and, lifting them up above the general level of the country, deposites them upon it. In this way, I have observed considerable portions of rich plantations, distant several hundred yards from the edge of the river, buried several feet deep beneath a barren sand. At other times, the freshets plough the whole of the vegetation up from the ground for thirty or forty acres, and deposite it in a mass, with all its timber, upon some beach lower down. This is the general character of the Arkansas as I have observed it for several hundred miles, and I have been told by those who have visited it nearer to its sources, that it has, in some places, abraded the whole surface of the country for several miles in width. These abrasions are more interesting to the geologist than to the planter, for the fresh fracture enables him to trace for great distances the party-colored deposites, alternating with each other, some white, some red, some gray, and often intermixed. Some parts of the banks are from one hundred to one hundred and thirty feet high, and assume an important appearance in a country where much of the surrounding land is at a low dead level. About fifty miles from Little Rock the Red Pine bluffs occur, which the river is fast wearing down. Twenty miles lower down are similar bluffs of a lighter color, called the White bluffs, and about thirty miles lower down are the Pine bluffs, which are higher than the others. At the Red Pine bluffs there is a bed of limestone, seen at low water, formed of broken down oyster shells, like those in the Saline river. This is the only calcareous deposite within my knowledge in the banks of the Arkansas east of Little Rock, except one I afterwards saw in the high banks at the post of Arkansas. They all present a fine study of fluviatile deposites, not only in the party-colored seams of the old banks, but where they are at present forming on the surface of the country. This immense river has its sources six or seven hundred miles apart. Its southernmost branch, the south fork of the Canadian, receives streams which rise near the thirty-fourth degree of north latitude; its most northerly source is from the Rocky Mountains, between 39° and 40°; and its most eastern sources, including the heads of the Verdigris, Neosho, and Illinois, rise about 38° north latitude, at least six hundred miles from the central and principal sources in the Rocky Mountains. The southernmost sources flow through an ancient deposite of red argillaceous matter for several hundred miles, and it is this which colors the Canadian and its branches. The western and northern sources bring down mineral matter of different colors, but to the east the sources take their rise in a high siliceous country, and their mineral deposites are indicative of their origin. The branches of the Arkansas, included in this area, are numerous; the Illinois, the Neosho, the Verdigris, the Canadian and its two principal tributaries, are all fine rivers, and would belong to the class of most important European streams. They are of unequal length, and, being separated by great geographical distances, are subject to. increase their volume at distinct periods; and this volume, on account of their unequal length, being emptied at distinct times into the main channel of the Arkansas, the deposites which this last leaves, in its irregular progress to the Mississippi, are characteristic of the mineral substances which its tributaries and their branches pass through. The Canadian, which passes through a red earth, has always dull red waters, like those of Red river, arising still further south. We are, hence, enabled to assign the red deposites to the materials transported by that stream, whilst the *There is a fine instance of this at Mons. Barraques, about one hundred and forty miles from Little Rock. whiter and siliceous deposites may be attributed to the northern and eastern tributaries, whose waters, including those of the Poteau, that comes in further east, are all more clear. Those who have had opportunities of observing the eccentric movements of floods of this class, soon learn to distinguish what circumstances, whether arising from partial eddies, owing to the change of level produced in periods of inundation, or from ordinary mechanical causes, have produced both the regularity and irregularity of deposites; and how it is that blotches of mineral matter, both large and small, are found enclosed in deposites of a homogeneous character, differing from them, just as the whiter matter of the eastern branches of the Arkansas, brought down by the Illinois, is found enclosed in the extensive beds deposited from the waters of the Canadian. It is in the study of phenomena of this character, where fluviatile deposites are effected upon so immense a scale, that perhaps an explanation of many different pretensions of mineral matter, observed in older indurated rocks, may be suggested. I observed many superficial deposites which had been made, perhaps within ten years, by the annual inundations: layers of white clay, sometimes of white sand, with occasional intermixtures of both superimposed upon each other, and at times large blotches of whitish clay, were enclosed in a regular deposite of red. One day I followed, for a considerable distance, an old dry bed which the river had abandoned for a new passage at the foot of the right bank, isolating a high ridge between the old and new beds, where the young wood was beginning to grow very thickly, on a surface from whence all the timber had evidently been swept when the new passage was made. The inundation of June, 1833, had deposited about an inch of dull red argillaceous matter over a great part of this dry bed, which extended many miles into the country, and presented the appearance of a reddish sandy valley, about three hundred yards broad, containing many accumulations of sand and dead trees, the old sand bars and snags. Every thing bore a very desolated aspect; it was a huge chasin to appearance, furrowed out through a flat country by the temporary passage of a great river, which had not left a drop of water behind it. I saw no symptoms of animal existence, except the track of a solitary deer, and a few turkey buzzards wheeling about in the air, and scanning the surface in their characteristic manner, in search of carrion. Upon the edges of some of these ancient banks of the river are several Indian mounds, with trees sometimes growing on them, some of them about five hundred years old: great quantities of Indian arrow heads are strewed around, made of the siliceous mineral of the Washita hills, and some have been found buried several feet beneath the surface; facts which show that this alluvial country, which was possessed by a few bands of the Quapaws when the whites first began to occupy it, has been inhabited by the aborigines at a very distant period. It will perhaps not be found impossible hereafter to assign approximately some limit to that period, when the settlement of the country shall bring other data forward, which connect themselves with the geology of the country. It is true, the deposites made by the annual inundations are naturally too irregular and variable to afford systematic data for the computation of a period for the origin of these fluviatile beds; but whenever a careful inquiry of this kind is made, it will be found important to note them very accurately. It would not be a difficult undertaking to calculate the approximative amount of sedimentary matter brought down annually by the Arkansas, or any of the turbid tributaries of the Mississippi. The main rise of the Arkansas and Missouri, caused by the melting of the snows of the Rocky Mountains, usually takes place in June; and these rivers are irregularly swollen during the winter and spring months by rain: at these times they bear along the A set greatest quantity of solid matter towards the mouth of the Mississippi, consigning it to the ocean, which meets the deposites and distributes it into levels, to be probably laid dry at some future day, as the alluvial plains I have been speaking of have already been. The lowest state of the Arkansas occurs during the months of July to November, inclusive. During a portion of this time, it is often not navigable from the Mississippi to Little Rock. At this stage of the water, the current is sluggish, the water quasistagnant, and the solid matter held in suspension very trifling, although always sufficient to tinge the water. of experiments might be conducted, showing the mean quantity of sedimentary matter brought annually down during the rises of the river, and during the low-water periods. Furnished with the cubic quantity of solid matter thus obtained, and applying it as a divisor to the whole quantity of fluviatile deposite contained in the entire alluvial area, we might approximately assign a chronological period for the origin of these rivers, the commencement of these deposites, and the withdrawal of the ocean from these countries. The period of their fitness to receive the human race might thus be found to accord with particular indications of the existence of the aboriginal race.* I would respectfully suggest to the officers in garrison at the frontier posts on the rivers I have named, especially those at Fort Towson, on Red river, Fort Gibson, near the Arkansas, Fort Leavenworth, on the Missouri, Fort Snelling, Jefferson Barracks, and Baton Rouge, on the Mississippi, to institute experiments with this view. It would be important to have them conducted in various places, near the sources of the great rivers, immediately below the mouths of their respective tributaries, and at points near to where the great rivers disembogue. We should thus in time possess statements of the accumulating solid contents held by these streams in their progress to the ocean, and be able to give them a very extensive application. Since my return, and as this report was going to the press, I have seen, for the first time, an interesting paper by Leonard Horner, Esq., a distinguished member of the Geological Society of London, "on the amount of solid malter suspended in the water of the Rhine," which, in the hope it may encourage gentlemen in the army to undertake the experiment I have recommended, I shall append to this note. "The attention of geologists has been more particularly directed of late to the importance of ascertaining the quantity of solid matter held in suspension in the water of different rivers, as affording a measure of the amount of abraded stone transported to the sea, there to constitute the materials of new strata, now in progress of formation. "During a late residence at Bonn, I began a series of experiments on the quantity of solid matter suspended in the water of the Rhine, in that part of its course. Several interruptions prevented me from advancing beyond the first steps of my proposed inquiry; but having no immediate prospect of being able to resume it, I venture to offer even this small contribution to science, as the facts I ascertained may not be considered without value. ure. "I made two sets of observations, the one in the month of August, and the other in November. The apparatus I used was very simple, but answered the purpose perfectly; as it may be constructed in a very short time, and almost in any situation, the facility of making the observations ought to increase the chance of others of the same sort being made elsewhere. It consisted of a stone bottle, capable of containing about a gallon, and furnished with a cork covered with leather, and greased; a weight of about ten pounds was attached to the bottom of the bottle by a rope of such a length that, when the weight touched the ground, the mouth of the bottle might be at the desired distance from the bottom of the river. A rope was attached to the ear or handle of the bottle, by which it was let down, and a string was fastened to the cork. As soon as the bottle had reached its des tined position, the cork was withdrawn by means of the string, the bottle became filled with the water at that particular depth, and was then instantly drawn up. The water, as soon as drawn up, was emptied into glass jars, on which I had previously marked a certain measThe quantity of water on which I intended to operate was a cu bic foot, or 1,000 ounces, and I collected it at different times; for instance, after one-third of a cubic foot had stood in the jars for some days, I drew off the clear water with a syphon, and another third of water, fresh taken from the river, was added to the sediment left at the bottom of the jars from the first; that was allowed to stand, the clear water was again drawn off, and the last third was added in the same way. When this had stood a sufficient length of time, the accumulated sediment was removed to an evaporating dish, (a common saucer will do quite as well,) and carefully dried in a gentle heat. The dried mass was the amount of solid matter held in suspension in a cubic foot of water, and now in the state of indurated mud. "First set of observations.-The water was taken at the distance of one hundred and sixty-five feet from the left bank, and at a depth of six feet from the bottom of the river, the total depth of the river at that place being thirteen feet. It was in the month of August, and the Rhine was unusually low. The water in the river had a yellowish tinge, and was turbid; taken up in a glass, it was like the New river water, in London, after rain. The residuum, when dried in the manner above mentioned, weighed 21.10 grains. It was of a pale yellowish brown color, smooth to the feel, not grilly; and it effervesced Amongst the most interesting results of my late tour, I navigation, where fifty millions-and a much greater nummust enumerate, first: The establishment of the fact, from personal observation, of there being, in the State of Missouri and the Territory of Arkansas, an amount of the ores of lead and iron, of an excellent quality, not only more than adequate to any esti. mate of the domestic consumption of this nation, but such as may justify the expectation that it will form an impor-known regions in the same class with the most powerful tant element hereafter of commercial exportation from that part of the world. When it is considered that the sulphuret of lead forms, as described in this report, such an important portion of the solid rock at one point, and that it exists, in an equally profuse manner, perhaps, through various points for a distance of five or six hundred miles,* this language will not be deemed extravagant. But looking forward to the future prospects of these regions in the mining branches of industry, who, that has had but a glimpse of those fertile alluvial territories to the south, penetrated by so many thousands of miles of river briskly, but was not wholly dissolved, when diluted muriatic acid was poured upon it. In appearance and properties it was undistinguishable from the loess [a yellowish gray foam] of the Rhine valley. "A cubic foot of distilled water weighs 437,500 grains; therefore, the solid matter amounted to the one twenty thousand seven hundred and thirty-fourth part of the cubic foot of water. Second set of observations.-The water was taken up in the middle of the river, and from about a foot below the surface. It was the month of November, and a great deal of rain had fallen some time before and during the observations. The Rhine was of a deep yellow, and more turbid than in August; but when taken up in a glass, it was not very different in appearance from what it had been then. The cubic foot of water, in place of being collected on three different occasions, was taken up on seven different days, with intervals of three days between each. The residuum, when dried in the same manner, weighed thirtyfive grains, which is the one twelve thousand five hundredth part of matter in one cubic foot of the water. "It was my intention to have repeated these observations at different seasons of the year, to have made a profile of the bed of the river from shore to shore at Bonn, and to have ascertained the velocity at different parts of the stream, so as to get a mean velocity; the depth of the river I had an opportunity of seeing, for there is a gauge at the port; but was obliged to leave Bonn suddenly, and could not accomplish my desigus. "The above experiments show that the quantity of solid matter suspended in water, which, in the mass, has a turbid appearance, may be very trifling. But the extent of the waste of the land, and of the solid materials carried to the sea, which even such minute quantities indicate, is far greater than we might be led to imagine possible from such fractions. It is only when we take into account the great volume of water constantly rolling along, and the prodigions multiplying power of time, that we are able to discover the inagnitude of the operations of this silent but unceasing agency. In the absence of more accurate data for my calculations, for the sake of showing how large an extent of waste is indicated by water holding no more solid matter in suspension than is sufficient to disturb its transparency, I shall assume that the Rhine at Bonn has a mean annual breadth of twelve hundred feet, a mean depth throughout the year of fifteen feet, and that the mean velocity of all parts of the stream is two miles and a half per hour. These assumptions are probably not far distant from the truth. I shall take the average amount of solid matter in suspension to be twenty. eight grains in every cubic foot of the water "If we suppose a mass of water of a foot in thickness, 15 feet in depth, and 1,200 feet in length, we shall have a column across the riv er containing 18,000 cubic feet; and 18,000 multiplied by 28 gives 504,000 grains of solid matter in that column. "A cubic foot of distilled water weighs 437,500 grains; and, if we take the solid matter as having a specific gravity of 2.50, a cubic foot of it would weigh 1,093,750 grains. "If the river run with a mean velocity of two miles and a half in the hour, 18,200 such columns would pass a line stretched across the river every hour, and 316,500 such columns every twenty four hours; (1,760 yards in a mile equal to 5,250 feet multiplied by 24 equal to 13,200, and 13,200 multiplied by 24 equal to 316.800.) If 316,800 columns be multiplied by 504,000 grains, and the pro duct, 159,667,200,000, be divided by 1.033,750, (the number of grains in a cubic foot of the solid matter,) we have 145,980 cubic feet of stone carried down by the Rhine past the imaginary line every twenty-four hours-a mass greater in bulk than a solid tower of masonry sixty feet square, and forty feet in height. If we multiply 145,980 by 365, we have 1,973,433 cubic yards carried down in the year; and if this process has been going on at the same rate for the last two thousand years-and there is no evidence that the river has undergone any material change during that period-then the Rhine must, in that time, have carried down materials sufficient to form a stratum of stone of a yard thick, extending over an area more than thirty-six miles square. How much further back we may legitimately carry our calculations, I leave it to those to fix who consider that there are any data to enable us even to guess at what epoch the Rhine was different from what it now is, either in respect of the vulume or the velocity of the stream, in that part of its course at least to which the present piper refers." North to the Ouisconsin country. VOL. XIV.--A 44 ber might be asserted-of North Americans have yet to establish themselves; where the amount produced of sugar and cotton, which excites the admiration of our own day, will be referred to as the germ of production hereafter; where, when populous cities, increased shipping, and well protected plantations, shall have placed these imperfectly portions of the earth; who can doubt but that a part of the immense wealth thus accumulated will be invested in working the inexhaustible mines which lay, as it were, at the very door of New Orleans, a city evidently destined to rank hereafter amongst the first in the world? If one nation can ever permanently undersell the others in those metals, it must be one possessing mines from whence they can be extracted with equal facility as from those in question, and exported with so little charge. I consider it also as a result of great importance, that the extensive investigations which I have so recently made, have gone, without exception, to strengthen the opinion I submitted to the Geological Society of London, in 1828, as to the series of rocks in the United States being the natural equivalent of that observed in Europe, from whence we may infer that the causes which operated to bring the rocks there into the particular order of superposition they preserve, have operated here, and probably have acted upon the whole crust of the earth. It is true we have not yet found that remarkable portion called the oolitic formation, lying above the coal measures, but this is only a part of the series; and in every country where geology has hitherto been practically studied, some part or other of the series is wanting. At many points of our Atlantic coast, including the city of Washington, there is no rock intervening between the superficial detritus and the gneiss, which is the lowest rock but one of the whole series. calities, with imperfect arrangements of this nature, are like a harp, where, though some of the party-colored chords may be wanting, yet the rest are there, and preserve their unchangeable superposition to each other. This correspondence of structure will result in making the principles of the science of geology, like those of geometry, applicable everywhere. Lo It is a remarkable circumstance, as I had occasion to announce in 1828, that, with the exception of the tertiary and subcretaceous beds of the coast, nothing more recent than the coal-bearing series had been found in the United States. A fact so unusual in a continent of such great extent as North America, can hardly be attributed to denuding causes, and would rather lead us to the inference that this part of the globe has in fact emerged from the ocean before the continent of Europe did, and that, geologically speaking, in reference to the history of the earth, this has very strong claims to be called the old world. If no denuding causes adequate to the phenomenon have been in action, we must either adopt that opinion, or suppose that, whilst other parts of the subaqueous world were receiving sedimentary deposites, the waters of the occan, which covered the vast area, devoid of the entire oolitic system, were situated so as not to receive any sedimentary materials. The opinions I communicated in 1828 have been confirmed by my late tour, and strengthen the conclusion to which my judgment has been for some time coming, that this continent is much older than the European continent. It has not, however, been found easy to suggest for the duration of geological events, periods of which our own chronological methods shall be the measure. In the other hemisphere it has been found that species have not changed materially during the present order of things, which, as far as we can judge, comprehends the existence of man, and does not include that portion of time when any of the tertiary beds became dry land. There is scarcely any reason to suppose that the remains of man have been found in transatlantic countries out of the present order of things, executed in a much more creditable manner-presents the and none whatever in this hemisphere. For the produc- geological formations which occur from the New Jersey tion of our deltas, it must be evident that the full measure coast, on the Atlantic ocean, to Red river, on the Mexican of our chronologies would be wanting. If, therefore, du- confines, along an inflected line of about one thousand six ring so long a period as they comprehend, no material | hundred miles, which I have personally examined. The changes have been produced in species, we cannot but course to Nashville is south of west; thence, to Louisville, infer immense durations of time necessary to effect so east of north; thence, to St. Louis, nearly west; and the great a progression in organic existence, as is observed remainder of the section is on a course west of south. in the difference between recent and extinct shells, ani- The inclined lines were intended to represent the transition mals, and plants of the tertiary formations. What then beds, and the horizontal ones, which come in at the Cummust be the relative antiquity of this continent, if so berland mountain, to represent the horizontality of the cargreat a portion of it became dry land before the de- boniferous limestone. The short lines, about one-fourth position of the oolitic system in Europe, itself compre- of an inch, represent the localities where bituminous coal hending phenomena that seem to set at defiance every hope was seen. It would not have been practicable to introduce to compute a rational duration of time for their separate a regular scale of elevations, even had I possessed the maproduction? terials for one. I mention here, however, a few localities by way of approximation. The Alleghany ridge, through which the Potomac cuts west of Cumberland, rises between Frankstown and Johnstown, Pennsylvania, to the height of two thousand two hundred feet above tide water level. The same ridge, west of Cumberland, in Maryland, is two thousand seven hundred and fifty-four feet in height. Between Covington and the Great Falls of the Kanawha river the ridge measures one thousand nine hundred and ten feet. These are, however, depressed points selected by engineers for canal communications. Many of the summits exceed three thousand feet, and the general elevation of the ridges in the Arkansas Territory over which I passed appeared to me somewhat, though not much, inferior in height to those of the Alleghany ridges. Very respectfully, It will be felt, also, as an interesting step in the progress of geological knowledge, that we shall be enabled hereafter to trace with accuracy the littoral line so clearly made out by the subcretaceous fossils of the same genera which have now been continuously found for near two thousand geographical miles. It is evident that the ocean retired cotemporaneously from this line, either from the deepening of its bed, produced by distant causes, or from the elevation of the land; and this is the geological period which may be fixed for the commencement of those great deltas of rich alluvial matter brought down by the rivers alluded to in this report, and which are hereafter to form so important a portion of the civilized earth. It remains for me only to state that I have made ample collections of minerals and geological specimens of the countries I have visited, all of which, when they reach this city, will be placed at the disposition of the Government, G. W. FEATHERSTONHAUGH, [The map accompanying the report is necessarily omit The section which accompanies this report—and which the state of the arts in this country well admitted of being | ted.] |