enemy. On Thursday last, two companies of his cavalry had a skirmish with the enemy on Cotile Bayou, they having been sent out to reconnoiter, on account of a report that the enemy were constructing breastworks of cotton at Judge Boyce's bridge. It was found that the enemy had about 1,000 dismounted cavalry and several pieces of light artillery. We had 1 man wounded and several horses killed. Three dead bodies of the enemy were found on the field and buried.

On the following day the whole cavalry force was sent out, with 200 infantry and one piece of artillery, on the gunboat Switzerland, to attack the enemy, who fled, on the appearance of our force, in three directions, closely pursued by our cavalry. He then took position at Cane River, and only a few of his pickets had since ventured down to Cotile Bayou. Six prisoners were captured who belonged to Colonel [W. P.] Lane's Texas cavalry, which left Texas two weeks since. Letters found in the mails seized indicate that there is but a small force at Mobile, much of it having been sent to re-enforce Johnston.

The indications respecting Port Hudson are that the garrison there has been much diminished, but how much is uncertain; probably the garrison does not now exceed 4,000 men. Four hundred head of beef-cattle were sent to Port Hudson from this side about a week ago. It is reported that they have only a picket at Bayou Sara.

Lieutenants Hill and Whitside arrived here to-day from Barre's Landing. They report about 1,000 bales of cotton still at Barre's Landing.

It seems that the enemy must be concentrating everything available on Rosecrans in the west, and he is probably doing the same against Hooker in the east-wise course.

General Grover's division crossed to this side to-day, and General Emory's division will cross to-morrow. I propose to send down the Sixth New York Regiment to Brashear and thence to New Orleans on the first opportunity, probably day after to-morrow. The Union leaves to-morrow morning with sick, contrabands, and mules for Brashear.

I do not quite like the intelligence from Hooker's army, but hope for better luck next time.

I am, general, very respectfully, your obedient servant,

[GEO. L. ANDREWS,]

Brigadier-General of Volunteers, Chief of Staff.

HEADQUARTERS OF THE ARMY,
Washington, D. C., May 19, 1863.

Major-General BANKS,

New Orleans, La.:

GENERAL: I learn from the newspapers that you are in possession of Alexandria, and General Grant of Jackson. This may be well enough so far, but these operations are too eccentric to be pursued. I must again urge that you co-operate as soon as possible with General Grant east of the Mississippi. Your forces must be united at the earliest possible moment. Otherwise the enemy will concentrate on Grant and crush him. Do all you can to prevent this. I have no troops to re-enforce him. Both Burnside and Rosecrans are calling loudly for re-enforcements. I have none to give either.

I have strongly urged the Navy Department to send the monitors to the Mississippi River, but I am answered that they can do nothing against Vicksburg and Port Hudson.