 Complete the following phrase:  The 47th Pennsylvania Infantry, one of the regiments which initially served in the Eastern and Lower Seaboard Theaters, went on to become the only regiment from Pennsylvania to both fight in the Unions 1864 Red River Campaign across Louisiana and to have men confined as POWs at Camp Ford, the largest Confederate States Army prison west of the Mississippi River. After the 47ths return to the Eastern Theater in July of that same year, the regiment then participated in a brief encounter at Snickers Gap before engaging in the intense fighting of Sheridans 1864 Shedoah Valley Campaign in Virginia, including during the battles of Berryville, 