Table showing value of merchandise, in bond, exported to Mexico from district of Corpus Christi, from 1st of January, 1868, to 24th of May, 1870; also value of merchandise which passed through respective ports. Roma, value of merchandise.. Rio Grande City, value of merchandise.. Total $44,139 00 7,732 00 44, 221 00 96,092 00 Value of bonded goods which entered warehouse in customs district of Corpus Christi, from June 17, 1867, to May 24, 1870, $135,890. Number and tonnage of vessels entered and cleared in customs district of Corpus Christi, from July 1, 1868, to May 1, 1870. Entered: Number, 253; tonnage, 45,803.90. Amount of produce and merchandise received and shipped at Corpus Christi, from 1st of January, 1869, to May 20, 1870, compiled from books of wharf agents. Merchandise received: 69,500 pounds assorted; 2,081,447 feet of lumber; 1,585,475 shingles. Produce shipped: Wool, 1,908,829 pounds; dry hides and skins, 2,220,953 pounds; tallow, 846,278 pounds; salt beef, 100,159 pounds; lard, 21,514 pounds; bones, 75,000 pounds; pig-lead, 340,651 pounds; rags, 2,381 pounds; horns, 5,198 pounds. ARANSAS PASS. By a comparison of the Coast Survey maps of 1853, 1868, and the map herewith submitted, February, 1871, it is seen that the channel is constantly encroaching on Mustang Island, (on the south,) while St. Joseph Island is accumulating, and making out with a low sand flat, with shoal water at considerable distance from the shore-line. In 1853 the channel through the bar was parallel to its present position, but farther north. In 1868 it was about perpendicular to its present position. In 1869 a work was begun by private enterprise, to improve the channel through the bar by running out lines of jettees from the St. Joseph Island shore, to cut off a secondary channel near this shore. These jettees, crates, or caissons, as they are variously called by the builders, were made of live-oak poles, spiked together in the general form of a triangular prism, and placed longitudinally. Each crate was about 8 or 10 feet long, 6 feet high, and 6 feet wide at the base, resembling, when in position, the roof of a house, with only rafters in place. These crates were ballasted with a few hundred-weight of stone, filled with brush, and sunk in two or three parallel rows, in the position described. They were expected to act as a nucleus, about which sand would settle, and close up the secondary channel, thus directing the flow of the water directly through the channel in the bar. From the fact that the secondary channel has shoaled about 2 feet, and the main channel deepened about 2 feet since placing the crates, it may be supposed that they have contributed to produce this result, but one of the oldest pilots holds that the change is due to storms, and would have taken place without any work. Owing to the constant erosion of Mustang Island, and consequent shifting of the pass to the south, in a few years the jettees mentioned will have no effect on the current, being left on St. Joseph's Island, which follows the channel in its progress south. It seems probable that the channel must continue to shoal, unless the erosion of Mustang Island, and consequent shifting and widening of the channel, can be prevented. The scour is at least 36 feet deep; hence any attempt to protect Mustang Island by a revetment would be expensive, requiring piles at least 45 feet in length, if a pile revetment were attempted. As any plan for deepening the channel through the bar by the action of the current must require the protection of Mustang Island against the encroachment of the channel, before attempting jettees or piers from the Gulf-shore line toward the bar, the means of affording such protection is the first question for consideration. Turtle Cove affords no passage over a foot in depth to Corpus Christi Bay; hence there is no current of importance at its mouth. The present entrance to Corpus Christi Bay is through Corpus Christi Bayou, a crooked channel of scant 5 feet of water, which enters Aransas Bay about ten miles from Aransas Pass. A canal 150 feet wide and 12 feet deep, from the mouth of Turtle Cove due west to Corpus Christi Bay, would allow sailing-vessels to pass in either direction at almost all times with the prevailing winds, thus opening the best bay on the Gulf as a harbor for vessels which could enter Aransas Pass. It is probable that such a canal would have a current of sufficient power to modify the action of the channel-current on Mustang Island, checking, and perhaps stopping, the erosion for some distance below the mouth of Turtle Cove. Harbor Island, on which the light-house is situated, and through which this canal is proposed, is flat and marshy, composed principally of shell-mud. The mouth of Turtle Cove has a sandy bottom, a part of the sand deposit which extends in front of the light-house. A revetment to the north side of such a canal, extending from the shore of Harbor Island to the 12-foot curve in the channel, would serve the double purpose of protecting the mouth of the canal from the sand-deposit above, and acting as a wing-dam to deflect the current of the ebb-tide from Mustang Island. To direct the current of ebb-tides from the pass constantly through the same part of the bar, it will be necessary to shield this current from the action of the littoral current. The littoral current varies with the wind, and, according to the testimony of pilots, its direction is up the coast when the wind is south of southeast, and down when the wind is north of that quarter. They agree in stating that the direction of this current is up the coast during the greater part of the year. Its maximum rate is variously estimated at from one to two miles per hour. To protect the ebb-current of the channel from the action of the littoral current until the former reaches the bar, would require at least one jettee or pier extending from the shore-line to the bar, a distance of about 4,800 feet. Of this distance about 2,000 feet would be in water less than 12 feet deep. The remaining 2,800 feet would be in water 12 to 18 feet deep. The first 2,000 feet would probably produce a perceptible effect on the bar, but the extension of the deep water of the channel across the bar could not be expected unless the jettee were carried across it to deep water outside. A gradual extension of either or both island shores toward the Gulf could probably be effected by a system of groins or works similar to the rows of crates mentioned as having been placed on the end of St. Joseph's Island, but the bar would probably keep pace with such shore-line extension in its progress outward. Even if the 4,800 feet of jettee could be built at once, it is possible that a few years would suffice to extend the shore-line so that a sand-deposit might be expected near the end of the jettee where the channel-current would be exposed to the full effect of the waves and the littoral current. It would not be safe to attempt any jettee from Mustang Island toward the bar before securing the end of this island from further encroachment of the channel, and any attempt to narrow the channel from the side of St. Joseph's Island would only increase the action of the current on Mustang Island, probably without producing any beneficial effect on the bar. I submit two plaus, with estimates of cost of each, for the protection of Mustang Island, from the mouth of Turtle Cove to the shore-line of the Gulf. The distance is 1,550 yards. First. A series of groins or pile-work at points shown on the map, normal to the shore-line; the groins being built to present a concave front to the current, whether at ebb or flood tide; each groin to be 100 feet in length, measured perpendicularly from its base, which is 200 feet in length on the shore; the sides of each groin to be formed on an arc, with radius of 100 feet; these arcs being tangeut to each other at the point of the groin, and also tangent to the base of the groin at the ends of the base; the interior of the groin to be filled with brush and stone, and the outside near the point to be riprapped with stone. Stone of a sufficiently good quality for this purpose can be had at Rockport, about twelve miles distant. I was told by prominent citizens that the expense of delivering it at the pass would not exceed $10 per cord. Estimate of cost of one groin, as described. 566 piles, average length 24 feet, cost each $6 Driving 566 piles, at $2 per pile Cutting off and capping same, at 50 cents each. 200 cords of stone, at $10 per cord. 100 cords of brush, at $2 per cord.. 700 drift-bolts or spikes, 350 pounds, at 7 cents. 200 screw-bolts, 1 inch diameter, 12 inches long, with washers, 1,000 pounds, at 8 cents per pound.. 3,684 feet (board measure) pine plank, at $30 per M $3,396 00 1,132 00 283 00 2,000 00 200 00 24.50 80.00 110 52 7,226 02 28,904 08 2,890 40 31,794 48 Second. A system of riprap extending from near the mouth of Turtle Cove to the Gulf-coast line, a distance of 4,500 feet. Estimating for one cord of stone to each foot of shore-line: 4,500 cords of stone, at $10... Add 10 per cent $45,000 00 4,500 00 49,500 00 Estimate for a canal from the mouth of Turtle Cove, due west, (true,) to Corpus Christi Bay; dimensions 150 feet wide at bottom, 10 feet deep at mean low water, four miles long. As Harbor Island is barely out of water at ordinary high water, and the proposed direction of the canal is through extensive mud-flats covered with water, the estimate may be safely made on the supposition that there is no excavation above mean low water. Cost of excavating 1,251,555 cubic yards, at 50 cents per cubic yard Add 10 per cent Total... $625,777 50 62,577 75 688,355 25 Second: To form a base for a system of ripraps by building of palm, palmetto, cabbage, or mangrove, triangular prisms 10 feet long, 6 feet on each side, with cross-pieces 12 feet in length, bolted to base, one at each end. These prisms filled with stone and placed parallel to the shore-line in 5 feet of water, with stone filled in behind to high-water mark. This system to extend from near the mouth of Turtle Cove to the Gulf-coast line, a distance of 4,500 feet. Estimate of cost of revetment or jettee at north side of entrance of canal, at mouth of Turtle Cove, as indicated on map; 1,400 feet long, 10 feet wide. 1,420 piles, average length 25 feet, at 25 cents per linear foot.. 1,400 piles, average length 15 feet, at 25 cents per linear foot Driving 2,820 piles, at $2 each.. $8,825 00 5,250 00 140 cross-ties, 8 by 10 inches by 10 feet, 9,3334 feet, board measure, at $30 per M...... 5,640 00 1,000 screw-bolts, 18 inches long, 1 inch diameter, with washers, 6,000 pounds,at 8 cents per pound 2,820 linear feet wall-timber 8, by 10 inches, 18,800 feet, board measure, at $30 per M. 280 00 564 00 480 00 1,410 00 2,000 00 4,000 00 28.449 00 Cutting off and capping piles, at 50 cents each. Filling brush, 1,000 cords, at $2 per cord... Stone, 400 cords, at $10.... Add 10 per cent. Total..... 2,844,90 31,293 90 The cost of building a jettee from Mustang or St. Joseph's Island toward the bar, which would be able to resist the action of the storms upon the quicksand foundation, must be an insurmountable objection to any such experiment. The stone to be obtained at Rockport is too poor in quality for use in so exposed a work. Such a pier, if built in the shoal water on either side of the present channel, would be exposed to a change in the depth of the water on the channel side, which would be fatal to any work whose foundations were not below the scour. Pile-driving would be very expensive, owing to the exposed situation, indeed hardly practicable; and the presence of the teredo naralis prevents the use of any timber suitable for making crib-piers. No estimate for such a work is presented. The above estimates are made to show the cost of a beginning of any harbor improvement on this coast. Whether the necessities of commerce demand such extensive outlays or not, is a question which has been answered negatively by former reports on the subject. The commerce of this region has increased rapidly since the war, and the city of Rockport, which has been built entirely within the past four years, has now a population of about 1,500. Rockport is situated north of Corpus Christi Bayon, on Aransas Bay, about twelve miles from Aransas Pass. Its wharves are protected from north winds by Nine-Mile Point, but are exposed to easterly winds. It is in the collection district of Corpus Christi, and is the point for the reshipment of freight for that place. The following list of exports and imports of Rockport for the year ending March 1, 1870, is compiled from the books of the wharf company: Exports.-Wool, pounds, 973,165; hides, wet salt, number 39.207; tierces of beef, 1,481; barrels of tallow, 2,882; tierces of lard, 35; number of calves, 3,119; number of sheep, 1,866; empty beer-kegs, 233; hogsheads dried beef, 23; bales of cotton, 29; kegs of lead ore, 4; pounds of dry hides in bales, 108,633; number of loose dry hides, 9,950; barrels of beef, 1,564; hogsheads of tallow, 556; number of beeves, 7,441; number of horses, 596; number of hogs, 1,547; boxes merchandise, 71; boxes beef, 84; bales of rags, 16; half barrels of beef, 37; coin, $15,442. Imports.-Assorted merchandise, per steamship from New Orleans, 145,782 barrels. the shore. PASSO CAVALLO. Passo Cavallo, the entrance to Matagorda Bay, is situated in the collection district of Saluria, between Matagorda Island on the south and Matagorda Peninsula on the north. It presents the same general characteristics as Aransas Pass, but on a much larger scale. Its history, like that of Aransas and Corpus Christi Passes, shows a steady deterioration as a harbor, and a constant shifting of the channel to the south. The constant shifting to the south of these three channels, which is a well-established fact, indicates some general cause for such change; and the historical fact of the deterioration of these harbors in the same time leads to the inference that the shoaling is due to the change in position. The general cause for the change is probably the prevalent direction of the winds, which have the greatest effect on the southern shores of the passes. The most rapid erosion has taken place during high tides accompanied by easterly winds. In August, 1863, a violent storm of this description swept away the whole east parapet of Fort Esperanza, an earth-work revetted with turf, situated on Matagorda Island, about-half way between the light-house and Bayou McHenry. The parapet was about 9 feet high, and when built, during the war, was about 100 feet from In 1854 a remarkable storm occurred, which reduced Pelican Island to a mere sand flat, hardly above ordinary high water. Before this storm it had grasscovered sand mounds, about 20 feet high, and fresh water could be obtained by digging in the hollows. The storm began by a southeaster, which filled Matagorda and Espiritu Santo Bays unusually full of water; then, changing to the northwest, the wind drove the water of the bays through the channel and over the end of Matagorda Island and Peninsula. The direction of the channel was changed considerably to the south, and its depth increased to 13 feet, but it shoaled to 8 feet in 1856, and at present 7 feet is all that can be depended upon, although vessels drawing 83 feet enter by waiting for a very favorable tide. In the storm of 1854 four vessels were blown from their anchorage near Decrow's Point, and lost or wrecked on the point; but in ordinary storms there is good anchorage from opposite Pelican Island to the bay north of Decrow's Point. Beside the channel between Decrow's Point and Pelican Island, there is one much larger between Pelican Island and the shoal opposite the light-house. This channel at present is almost equal to the one generally used below the light-house, having at good tides about 7 feet of water, and a breadth of about 1,500 feet. Every storm, however, changes the position of the system of shoals running south from Decrow's Point. A line drawn from the extremity of Decrow's Point to the light-house passes through a channel on the north of Pelican Island, 23 feet deep and about 400 feet wide, and the average depth of the whole channel north of Pelican Island, on this line, is 9 feet. The coast survey of 1856 gives but 12 feet north of Pelican Island, on the same line, with an average depth of 6 feet. Changes equally marked may be seen on the south side of the island. Pelican Island itself has shifted its position to the north about three-fourths of a mile since the survey of 1856. Vessels, once inside of the bar, can carry 24 feet to the anchorage, north of Decrow's Point; 12 feet to opposite Alligator Head, and about 9 feet to the wharf at Indianola, formerly called Powderhorn, now the principal town on Matagorda Bay. I found an idea generally prevailing among the citizens interested in the improvement of the pass, that it would be easy to stop up the channel between Decrow's Point and Pelican Island, thus causing a greater current at ebb-tide to act on the bar. Decrow's Point, and a portion of Matagorda Island opposite, are low and subject to overflow in extreme high water. This is especially the case with Matagorda Island, where the salt water has killed the grass on about half the surface. In planting a signal-pole on this island, I found that, after getting through a crust of a few inches on the surface, I could easily thrust the whole pole, 8 feet in length, into the earth. The effect of any work closing Pelican Island channel would be much more perceptible on Matagorda Island than on the bar, which at present is about three-fourths of a mile from the shore-line of the Gulf; and any attempt to narrow the outlet of Matagorda Bay, without first protecting Matagorda Island by an efficient revetment, would be a waste of the money expended. Any plan for removing the bar by the action of an ebb-current must fail, unless the direction of the current is controlled and the force preserved till it is brought to bear directly against the obstacle. This would require a jettee from Decrow's Point to the bar, a distance of four miles, and a revetment of Matagorda Island from Bayou McHenry to the point below the light-house, also a distance of four miles. Both of these works would be principally on quicksand foundations, and both, especially the jettee, would be exposed to seas which only a massive sea-wall could permanently resist. Small works, such as pile groins or piers, will succeed in causing an accretion of sand during the continuance of ordinary tides and weather; but a high tide with strong winds will, in a few hours, sweep away the accretion of months, and the work which caused it. Such has actually been the history of some small pile-works attempted on the Matagorda Island shore. A permanent sea-wall or a solid pier of any kind, four miles in length, able to withstand the storms of a single year at the point, would require the expenditure of millions. Any system of dredging for deepening the water on the bar would require a constant outlay, for any channel deepened in this manner would fill up at the first moderate breeze. However, a fraction of the interest on the sum required to make a permanent channel by jettees and revetments would keep several dredges at work if weather would permit. The pilots say that the water outside of the bar is not smooth enough for loading vessels, with lighters, more than one-fourth of the time. Such loading, at this point. is rarely if ever attempted. These facts preclude the idea of deepening the channel on the bar by the use of any ordinary dredge. In speaking of the current of the passes, I have called it the "ebb-tide," for, although rivers empty into the bays, and have their ultimate outlet at the passes, the tidal current only is perceptible, flowing as rapidly in one direction as in the other. The extent of the bays and the effect of the wind completely obliterate the action of the fresh-water streams, as far as ordinary observations are concerned. That the ebb-current does deepen the passes through the bars, is shown by the fact that they are deepest in the latter part of winter, after the action of the northers, which generally blow after a full tide in the bays, caused by violent southeast winds. Concerning the practicability of improving either of the harbors in question, I beg leave to quote from the report of Captain G. B. McClellan to Brevet Brigadier General J. G. Totten, Chief Engineer, U. S. A., Ex. Doc., vol. 2, 1853–54, page 561 : at * # "I regard it as impossible to improve any of them (the bars on the Texas coast) by dredging, scraping, or any similar means; for, supposing that means may be found to overcome the difficulty of working under such circumstances, and that the channel were actually deepened to the required extent, it is certain that the same causes, which now operate in so constantly shifting the position of the channel, would almost immediately fill up any new one made by artificial means. It now remains to be considered whether it is possible to improve the bars by contracting or changing the direction of the channel by means of dikes, jettees, &c. The passes Corpus Christi and Aransas, have each but a single outlet, all exceedingly narrow, and rone admitting any further decrease in width. The only possible application of dikes in these cases would be to prolong the walls of the outlet until they reached a point very near the present position of the bar, in order to concentrate upon one spot the whole action of whatever outward current there might be. The ultimate effect of this would undoubtedly be the formation of a new bar outside; that, too, at no distant period. The immediate effect would by no means certainly be favorable, and the new outlet would be liable to be closed up by heavy storms, (subject to breaking out again,) as is now frequently the case with small inlets on the coast of Florida. With regard to the project of improving Pass Cavallo, by closing the Pelican Island channel, to which my attention has been called by the Department, I have, since my letter of January 13, given it an attentive consideration. Were the proposed dike constructed, the situation of affairs would be analogous to that now existing at the other passes; and I see no reason for believing that the strength of the new current would be much, if at all, greater than at Aransas or Corpus Christi Pass. Were the strength of the current increased, it would exert itself in cutting away more rapidly the point |