A HERO AT REST.---Colonel DANIEL S. COWLES of Hudson, New York, (brother of Judge EDWARD P. COWLES,) was killed in the assault at Port Hudson, on the 27th ultime. He commanded the One-hundred-and-twenty-eighth Regiment of New York Voluneers, made up in good part of the hardy young farmers of Columbia county, many of them men of wealth and high social position. Colonel Cowles was himself wealthy, stood at the head of the bar of Columbia county, was a widower, about forty years old, of fine physical development, being over six feet high. He went into the war as a matter of patriotic duty, telling his friends that he did not expect to survive it, but considering many such lives a cheap sacrifice for the preservation of such a country as ours. From a private letter just received from Major FOSTER, of the regiment, we gather that he died as the true soldier would wish to die, leading up his men to the enemy's works. He was killed by a bayonet thrust in the groin, and lived about an hour after he received the wound. He was carried a short distance to the rear by Sergeant BELL, who sup- ported him in his arms until he died. He was every inch a soldier, cool in council, brave in battle, polite in his intercourse with others, and happy in all his relations. His last words were:--"Tell my mother I died with my face to the enemy. Lord Jesus re- ceive my spirit." It is expected that his remains will arrive here shortly, and will be taken to Hudson for burial.