BANKS DEFEATED AT MANSFIELD.Grenada, April I9th.—A courier, with Shreveport da tee of tb© 9th, parsed Greenwood this morning, from Gon. Taylor, who reported a battle on the 8th below Mans-fiold, capturing two thousand prisoners, twenty pieces ot artillery, two hundred wagons and thousands of small arms.Our 1088 in officers was very heavy. Gen. Morton, Col. Nobio and Gen. Polignac were severely wounded.A later dispatch reports the capture of fifteen more guns and the euemy retreating.Gen. Steele is reported on the north and , lt;*ast of tbo Littlo Missouri river, awaiting’ reinforcements. Ilia army bad been sta-j tionary three days. Cabell and Governor Flanigan are on the uortheast, Maxey and Marmaduko in his front, Shelly, Fagau and Dockery in his roar, west, front ami south of him. T