quire a higher embankment than at any other place through the swamp. It will average from twelve to fifteen feet for a distance of one mile and three quarters.

A mile and a half beyond the De Hart swale is the bayou Bonne Idee, the banks of which are above the highest flood. The stretch of swamp last described, from the Couloirs, at the end of the Mason hills, to the Bonne Idee, is called the " Bœuf swamp," as the Bœuf river runs through the middle of it. It is 10 miles across, as I mentioned before, and the average height of embankment across it, exclusive of the high part of it before noticed, approaching the De Hart swale, is about seven feet. We cross the Bonne Idee, near the residence of Mr. Murrell, who lives on its eastern bank, on an elevated piece of land. A bridge of 100 feet span, with 20 feet abutments, will suffice to pass the water at its highest stage.

After crossing the Bonne Idée, we take advantage of a bend in that stream lying nearly in our course, to follow its banks for two miles, which, being above the freshets, will require a bank not higher than two feet; thence we descend by a very gentle slope 1 mile, through another piece of swamp, called the Gallion swamp, to the Gallion bayou; and beyond it still another half mile to the end of the swamp, the edge of Prairie Mer Rouge, on the land of Captain A. A. H. Knox. The three divisions of the swamp which I have named-that is, the Mason, the Bœuf, and the Gallion swamps-have no communication with each other north of our line: this may be inferred from the fact that the highest floods in the several divisions do not occur at the same time, or even in the same year. The streams from which they are named have, therefore, independent channels, the banks being sufficiently high to prevent the water flow. ing from one to the other even in floods. In fact, between bayou Mason and the river Bœuf there is no communication; while the Bœuf, Bonne Idee, and Gallion do not unite until they have flowed several miles towards the south. Hence the height of the freshets is not the same in these swamps. This is most perceptible in the case of the Gallion and Bouf; the flood of the Beruf coming from above, while that of the Gallion, being formed by the back-water of the junction, makes a difference of ten feet in the relative levels of the highest water.

From Lake Providence to the edge of Prairie Mer Rouge the line conforms generally to the course of the road usually travelled, but cuts off its bends. In a straight line the distance between these points is 36 miles, by the usual road 43 miles, and by our line 39% miles. The actual survey was carried over the ordinary road, and the place for our projected line fixed by authentic information and by reconnaissance. I derived much information from James C. Drew, esq., and Captain Maxwell, surveyor, both of Lake Providence; from Mir. Murrell and Mr. Blackman, both of whom live in the swamp, and are highly intelligent in regard to it; and from Captain Knox, of Prairie Mer Rouge, who has given his mind very fully to the subject.

I have also availed myself of the information of A. C. Wooldridge, esq., engineer of the State, who had previously carried a survey over the same region. As the matter of constructing a road over this country-the dreaded Mississippi swamp-is the only real or unusual difficulty which was anticipated on the route, I have to state that I consider these difficulties to have been much exaggerated, and that the swamp is not impracti cable for the construction of a permanent work, at reasonable cost. The

material is not properly that of a swamp or morass, but merely the deposite from the waters not yet high enough to escape the annual overflows. When dry, it is tenacious and firm, which character it maintains to indefinite depths.

Mr. Murrell's well, on the banks of the Bonne Idee, 27 feet deep, and lower than the bottom of the bayou, showed at the bottom gravel as large as a hickory nut, mixed with a chocolate-colored clay. In certain places in the swamp, standing water does not penetrate below a few inches. Hence an embankment of any weight may be sustained, and constructions of masonry be made permanent by a good platform foundation below. Neither is the soil of a quality to "run" in still water, though in certain cases it might be advisable to give the sides of the embankments a flatter slope than is usual.

Timber of excellent quality abounds; the "over-cup oak" is the prevailing growth of the swamp, and no timber is better for constructions of the character we are discussing.

I saw the string-pieces of a bridge over the Bonne Idee which were built of this timber. It was partly submerged in ordinary seasons, and entirely so at times of flood, the weight being sufficient to keep it from floating.

This timber was perfectly sound, although it had been lying ten years in that very trying position. The soil of much of the country is proper for bricks; hence with durable timber, good earth for embankment, and materials for brick, we have at hand all the requisites for the road.

I conclude, therefore, that there is no objection on account of unusual difficulties of construction, excepting the interruption and injury to incomplete works from high water, which latter may be guarded against by bringing the embankments, as far as constructed, to their full heights, and when the water is about to rise, protecting the extremities by revetments of timber and plank. The embankment of a road always above water would be, for the greater part of the distance, less than ten feet in height, and never twenty feet, excepting for a few hundred feet in length at the approaches of the streams. Hence the cost will not be so formidable as has been imagined. But the great question is, if the construction of such a bank across the whole swamp will not be making a dam to hold back the freshet water, and thus bring it to a higher level, doing injury to the country above and to the work itself. It would seem that, if there were any impediment to the movement of the immense mass of water which, in seasons of flood, covers the country for many miles inland, it would cause the water to rise against and over the bank, and finally sweep it away after having done great injury to the upper country. course, if openings of sufficient magnitude be not left through the embankment, such will be the effect, though less in degree than would be produced by corresponding circumstances in a mountainous region, where the floods rush in from their sources, or where the face of the country has a considerable slope. But there is no reason why openings of sufficient magnitude should not be made, for these, as will presently appear, need not be so considerable as would be judged without observation. The highest floods come from the water escaping over the banks of the Mississippi and lower Arkansas rivers, where they have not been sufficiently leveed, or where the levees have been broken away. This body of water spreads itself over a wide extent of flat country, and continues to deepen

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until the surface attains the level due to its source. At this point it stands a long time, having a scarcely perceptible current, excepting towards the streams of drainage, and in the beds of those streams. This is the universal statement of the inhabitants, and observation confirms the ac-. count. Thus we do not see in the swamp any evidence of the passage of large bodies of water with a swift current: on the contrary, every evidence is against it, amongst which I may cite the instance of the present bridge over the Bonne Idee bayou, which being built for use in low stages, of umber very little heavier than water, kept to its place by a few stakes, and resting partly on the bottom, is covered at seasons of floods by fifteen. feet of water; and though almost ready to float, is not moved out of position.

Now the Bonne Idee is one of the streams of the Bœuf swamp, the largest of the three divisions of the swamp of which I have spoken; and all this goes to show that the flood-water has more the character of a lake than of a running stream, and that the size of the openings for passing the water bears no relation to those which would be necessary for passing a running stream of equal width and depth. A consideration of the cause of these floods, namely, the escape of the Mississippi waters from above, and those of the lower Arkansas, will show that openings sufficient to pass these escape waters are suflicient also for draining the swamp. If there were a break through the bank of the Mississippi as wide as the whole width of that stream, and enough water poured through this opening to lower the surface of the river, with a current of five miles an hour, one foot, these openings, which together would equal the width of the river through which the water would flow, with a depth of five feet, at the rate of one mile an hour, would suffice to pass the same amount of water. But in case even of a mistake on this point, in construction, if the openings be too small, but not extravagantly so, the sole effect will be to back up the water until by this greater head it attained a greater velocity, thereby causing an additional quantity of water to pass. The difference of a foot in the level of the surface of the water above and below the bank would cause the passage of a body of water under such bridges as we propose to construct, many times greater than would be passed with the ordinary sluggish movement of the waters.

This holding back of the water would continue but for a few days before it would be brought to equilibrium, or retire to its proper channels, and leave the cultivated country above ready for the labors of the planters. It is, moreover, not necessary to proceed rashly in the construction, as it is possible to prepare the work for travel before contracting the openings to their permanent minimum. For this I would in the beginning con struct none but the lighter embankments of earth; and as all the places of the heavier embankments are in the approaches to the openings, I would make a temporary substitute of trestles at those places, until by minute. observation precise knowledge on the proper permanent contraction could be obtained. By this means another object would be subserved, by providing a way for the transportation of the material for the permanent work. In accordance with these views, I would cross every channel in the swamp, large or small, by bridges instead of the small culverts whichwould be applicable in other localities; and by multiplying these until the total opening became sufficient to pass at least a foot of the surface water of the Mississippi river, I think the drainage would be entirely effected.

I have given nearly half a mile of bridging through the entire swamp, and have located it at such places as to secure a depth generally as great as ten feet, and frequently much greater, and have estimated accordingly. 'The material for the banks will be dug up from the sides, and the trenches so made may be used, at discretion, to lead the waters to discharge at favorable points, or by leaving traverses to hold it in pools, and receive the sediment with a view of refilling them. I have seen this latter process applied on a small scale, but very effectually, by individuals near the mouth of the Mississippi. It has been mentioned that at points through the swamp are spots and ridges of land elevated above the floods, from causes not always evident. The Mason hills, although generally but a few feet above the swamp, have a substratum of rock. There are many residents along the line of the road through these hills, and from some of them I learnt that in sinking their wells they had encountered a soft rock-in some instances "rotten limestone," in others "freestone." The water of the latter is very good-that of the former slightly foetid. The wells were from 30 to 40 feet deep.

Other elevated places through the swamp were the banks of the streams, which, according to the universal rule in this country, are higher than the country back of them.

This is as true in regard to the Mississippi as to the smallest bayous; the slope of the country from the bank of the Mississippi within the levee, to the bank of the Washita, a distance of 53 miles in a straight line, being 20 feet; and the highest water of the Mississippi 28 feet higher than that of the Washita. We availed ourselves of this law to obtain high ground for our line wherever the streams ran in the proper direction. More space has been given to the discussion of this part of the route than will be to any equal extent of the remainder, for the reason that little knowledge and much misapprehension exists on the subject of the practicability of ways through the "Mississippi swamp," and because the observations made have general application to other parts of the swamp than that over which the line was carried, and probably to the whole region subject to overflow formed by deposite from the Mississippi river.

On leaving the swamp our line passed near the residence of Captain Knox, over Prairie Mer Rouge, and in a distance of four miles came to an abrupt rise from the plane called the Red Hill, which is the border of a range of hills stated to begin at Pine bluff on the Arkansas river, and, running southerly, to cross the bayou Bartholomew about 12 miles above Prairie Mer Rouge; whence, continuing to the south, they cross our line and diminish in height, until they are lost in a table which reaches the Washita near the plantation of Senator Downs. We passed through the town of Bastrop, which is built on these hills, and found its elevation to be sixty feet above the prairie, and about one hundred feet above the water of the Bartholomew.

Two miles beyond Bastrop we strike that bayou at Point Pleasant, sixty feet lower than Bastrop, but still above high-water; we then followed the general course of the bayou on good ground all the way to the Washita, crossing bayou Saira and bayou Boeuf, which now discharge their waters into the Washita, but which in high stages reverse the direction of their flow and assist in carrying it off. These will require bridges. By following the bayou we are carried three miles to the south, out of our way, to Collier's point, the place selected for crossing the Washi

ta; but we avoid by this two crossings, with draw-bridges, of the Bartholomew, in case we continue to Collier's; or one if we consent to cross the Washita at the village above Collier's, which is an inferior place, and involving heavier expenditure. The line from Knox's just described, and which was traced on the ground, is not the one proposed for Construction. The bends of the Bartholomew are too abrupt, and the Bastrop hills would require deep excavation. I would, therefore, starting from Knox's, leave Bastrop about two miles on the right, or north, and run through the foot of the hills, where they have inferior elevation; thence to the southernmost point of the bend of the Bartholomew, on the plantation of Senator Downs, when we fall into the line as traced on the ground. From this southern point we turn northerly three miles, until we arrive on the bank of the Washita, opposite to Collier's point, which, as before stated, is the place selected for crossing. This projected line is on lower ground than that actually traced, being sixty feet lower opposite Bastrop than the ground occupied by that village: this is judged of by the depth of Beauchamp's well at his brick-yard; but the greater directness, easier grades, and lighter excavation through the hills, serve to sanction the selection of the route.

The material composing the Bastrop hills is sand and clay; the water stratum, SO feet in depth, is a fine white sand. The clay is good for brickmaking, and many are made in the vicinity. Where we strike the Washita we are on a table above the highest rise of the river, with a fine bluff (Collier's point) still higher than the table, on the opposite side, and no bottom land whatever.

The river at the highest water line is 600 feet across, and at the low-water line 310 feet. The bed is composed of sand and coarse gravel from the eastern shore to the middle, beyond which is a rock reef extending diagonally down stream to the western shore. At this river, at this point, the Mississippi alluvion ends, and the hilly country, frequently with rock in the hills, begins, and continues to the Red river. The Washita river rises in extreme floods 41 feet above the low-water mark, and has, when low, a depth of from 9 to 11 feet in the channel at Collier's point. The bridge to span it should be 600 feet long, with piers sixty feet high; and as the river is navigated, the bridge should be provided with a draw. Beyond the Washitaw we are on the ridge between that stream and the Loutre, a tributary entering about six miles below our crossing. We turn northwesterly, and continue on or near the crest of the ridge some seven miles, when it becomes necessary to decide whether to cross the Loutre and get on the ridge between it and the d'Arbonne, and then turn northerly, or to keep on the ridge northerly to the headwaters of the Loutre near Eldorado, in Arkansas, and then turn to the west on the old trail of the Quapaw Indians. The country beyond the Loutre was more populous, the roads in better order; supplies more easily obtained, and information more reliable and abundant.

It was decided to cross the Loutre, which we did at Brown's ferry. The country between the Washita and this point is rolling, but favorable for construction. There is rock in the hills, which became visible at Dr. Collier's spring, near the Washita, but not elsewhere. The soil is good for bricks, and many are made near our line. The Loutre will be crossed by a bridge of 150 feet span and 25 feet high, which is sufficient to pass the highest water. The western shore of the river is low, however, for