Complex sentence: During the weeks when ships were passing Mound Place on both their advance and retreat, the settlement was used as a temporary camp, during which Alcorn's cattle were slaughtered to feed Union troops, his carriages rolled into Yazoo Pass, and his fences destroyed.
Split into simpler sentences: During the weeks when ships were passing Mound Place on both their advance and retreat, the settlement was used as a temporary camp. It was reported that Alcorn's cattle were slaughtered to feed Union troops, his carriages rolled into Yazoo Pass, and his fences destroyed.