On Monday morning, November 2, at 3 o'clock, information was received by General Bee that the enemy were landing in force at Brazos. Preparations were immediately made for the evacuation of Brownsville; all means of transportation in the vicinity was impressed and loaded with army supplies, clothing, ammunition, &c. Thirty days' rations were furnished for 500 men, and sent with the retreating army. On the 3rd, about 12 m., the trains left Brownsville. At 3 o'clock a dispatch was received informing General Bee that the enemy were at Camp Russell, 10 miles below Brownsville, advancing in force. Arrangements had been made for the removal of all public property to Matamoras, and the steamer was to be at the landing to receive it at 4 p.m. of the 3rd, but about 3 o'clock the commissary building was discovered in flames, and the powder having been removed from the magazine to the building adjoining the commissary, so as to facilitate its movement to Matamoras, it was evident that in a few moments it would explode and jeopardize many lives. The sick and wounded were immediately sent to Matamoras, and the troops under command of General Bee, about 150 men, evacuated the post and proceeded immediately to the protection of the train laden with army supplies, which had started a few hours previous. The garrison and a large amount of clothing, camp equipage, &c., were destroyed on account of the incendiary act of some unknown person, who, without authority, fired the buildings.

The Mexican General Jose Maria Cobos, who had for the last ten months been in Brownsville, availing himself of the evacuation of the place, and with the ostensible purpose of extinguishing the fire which had spread over the city, organized a force of 200 men, and remained in command until the 5th, when the U. S. troops, under General N. P. Banks, occupied the place.

On the 6th instant, before daybreak, General Cobos crossed the Rio Grande and entered Matamoras at the head of his forces. He arrested Governor M. Ruiz and took possession of the city. The famous J. N. Cortina, who was in command of the Mexican troops on the Rigo Grande, joined General Cobos. It seems that the latter had previously secured the service of Cortina, who was at the time in command of that garrison, and also of the different detachments on the river. Governor Ruiz remained in prison until the morning of the 7th, when Cortina released him and informed him that he had ordered General Cobos and his aide-de-camp. Romulo Vila, to be executed. This was done at 9 a.m. The reason assigned for the execution of General Cobos was that by his proclamation of the 6th instant, addressed to the soldiers and the people of Matamoras, he had attempted to subvert the constitution, refusing to recognize the Juarez government.

Governor Ruiz was soon after notified by Cortina that citizen Jesus de la Serna, who had two years before been constitutionally elected governor of Tamaulipas, was the choice of the people. Governor Ruiz was offered to be sent into the interior under an escort of 25 men, but he eluded the vigilance of the sentinels and fled to Brownsville. It is not yet known whether Senor serna has accepted the appointment. In the mean time the bandit Cortina is at the head of affairs in Matamoras.

The General Government is so weak that it will probably come to terms with Cortina and his party. Senor Zambrano, the inspector of the custom-houses on the Rio Grande, is here at present. On the 14th instant he issued a circular declaring null and void all the acts