On the 9th of July, at about 10, A.M., each of the three subdivisions of the corps took the road designated for it. From this moment, commences a new epoch in our operations in Lithuania, and we shall give a separate detail of the proceedings of each of these corps, commencing with that of general Rohland, which was in the line of the enemy's pursuit, and was followed by his whole force. This corps, quitting Kurszany, took the road for Telze. On the night of the 10th, it arrived at Powenduny and the lake of Worna. Upon the road, it was joined by colonel Koss, who had been sent, as we have said, with his detachment, from Keydany, to construct a bridge over the Niemen, and who had extricated himself from the exposed situation in which this attempt had placed him. As the position was advantageous, and as our soldiers had need of repose after their fatiguing march, we remained there the whole night. On the next day, at sunrise, our camp was alarmed by the approach of the Circassian cavalry of the enemy. Our generals decided to wait the enemy's attack in their eligible position, and that day was one of most brilliant success. We will present to the reader full details of the events of that day, for they were of an extremely interesting character. The manoeuvres of all our forces were admirable; but those of the cavalry were indeed extraordinary. The reader will be astonished to find how much was done by a cavalry, fatigued, their accoutrements in disorder, and almost without ammunition, against a cavalry like that of the enemy, well mounted, with fresh horses, and in every respect in perfect order. COMBAT OF POWENDUNY AND WORNA.