From the Gulveston (Texa) New, June 25. Mr. J, A Echols, Secretary of tho Cominissioners sent by the Convention to the Indian Nation, refctirned recently. - He informs us that the Chickasaw Legis]ture passcd an act of secession by a utiammous vote, about the lst innt. A conevntion was to bo held by the Choctaws about the 14th inst., for the game purpose, and there is no doubt that natiou has also scceded. The Creek nation had a cousultation about the 12th of May, but they sat wifch closcd doors, and their action is not, therefore, ceitainly known, but as delegates to the SoutLern üonfedeiMcy were hnmediately sont no doubt is eutertaioed that an act of aeccssion was passcd. Gen. Douglas LI. Coopor, agent of tle United States, for tho Ghickasaws and Chocktaws, resigned sorae time siuce, has beeu adopted as a citizen, and is appoitited Commander-in Chief of all their forces Gen. Cooper is a Mississippian, and a relative of President Davis, Mr. Echols has brought to Austin tno treaties that havo been cxecuted by eomraissioners on the part of Texas and the Chickasaw natioD, with five wild tribes west of the civilized Indians, iucluding the Texas Reserves. The Kickapoos, the Delawares, the Keeckies, ete , bind thomselves to co-operate with the Southern Confedcwy against the Liucoln Government. Wo learn from Mr. Echols that a lcttor bas rccontly baeu recived from Col. Thornton, to the cöcct that the balance of the United Stutea traius that escaped the Texas troops at Fort Arbucklu, wcre cupturcd at Fort Gibson by the State troop of Aakansas. One hundred prisoners were captured, to whom an oath was admiuistered that they would not fight against the Confedérate States, when they wero pennitted to go, but all the property, arms, eto , wero retained.