JULY 25-AUGUST 2, 1862.-Expedition to Lake Pontchartrain, Pass Manchac, and up the Tchefuncta and Pearl Rivers, La., with skirmishers.

Report of Major Frank H. Peck, Twelfth Connecticut Infantry, commanding expedition.

CAMP PARAPET, CARROLLTON, LA.,

August 4, 1862.

SIR: The expedition directed by orders of July 25, 1862, from headquarters of this department returned on the 2nd of August. I have to submit the following report of our operations:

On the evening of July 25, with five companies of the Twelfth Regiment Connecticut Volunteers and a section of Captain P. E. Holcomb's Second Vermont Battery, I embarked on board the boat Grey Cloud, commanded by Lieutenant Buchanan, U. S. Navy. We left the wharf about midnight and arrived at Pass Manchac soon after daylight on the morning of the 26th. As we approached the bridge Captain Holcomb sent forward a shell from his Sawyer gun, which had the effect to draw from one of the houses a rebel scout, who immediately up the railroad in the direction of Camp Moore. He was fired after, and, as soon as a squad of men could be landed, was purchased across the island to the North Pass, where he plunged into the stream and escaped. We examined the buildings, and found the musket and equipments of the soldier, banks, parts of uniforms, and other evidence of recent military occupation. As the place was evidently used a rendezvous for spies and scouts I directed it all to be burned. The part of the bridge north of the draw had been previously destroyed. We burned the remainder. I am aware of nothing remaining at Pass Manchac more combustible than railroads iron and water-soaked piles.

In the latter part of the day we went up the North Pass, where we found that a beginning had been made toward repairing the bridge. We burned this also.

On the 27th we sailed up the Tchefuncta River. When opposite Madisonville we were fired upon by the guerrilla stationed there. We responded with a shot from one of the 32-pounders of the boat, sent through the street from which the firing came. Fortunately none of our party were struck, though a bullet passed disagreeably near to a group of officers standing upon the forward back.

At a point about 3 miles below Covington our farther progress was obstructed by three sunken gunboats, from which the guns have been recently removed. At this point we heard the shots of the guerrilla pickets, and the long roll was sounded in two different directions not far from us. We landed here and marched to Covington. On our way we learned that several bands, of from 6 to 50 each, had passed near us after our landing, with the intention of concentrating at some point to meet us. The advance sent forward into the city saw 5, mounted and armed, and fired upon them as they retreated, with what effect they could not tell, except that one or more of their horses were wounded.

We carried the national flag through the principal street of the city. White flags were hung from many of the houses, and citizens waited upon us to request that license might not be given for the commission of any outrage, such as their previous experience led them to expect. Of course no liberties were taken by our troops. Owing to the intense heat we shortly returned to our boat. On our way back we were informed by friendly persons that guerrillas were gathering on the banks