HORSE THIEVES.Trinidad, Colo., Sept 4.—A week ago John Jennings and others left Boston, Colorado, in pursuit of horse thieves in the neutral strip. The detachment overtook Billy Cornelius, an ex-marshal of Boston, and one companion—both of them horse thieves—drying their clothing after a rain. The two leaped upon horses bareback and escaped. Some stolen horses and arms were captured.Part of the detachment returned9 1with these while the rest followed the thieves. The pursuing party, reinforced by cowboys from about the Z H ranch, it is believed were guided by the flight of Cornelius and his companions to the principal rendezvous of the terrible band of thieves who are a scourge to southeastern Colorado. It is hoped that the reported battle has resulted. in the destruction of the main camp of outlaws, though here and at Folsom and and Clinton there are no particulars, only a meagre report of a pitched battle.