Complex sentence: Lamson, discouraged at the removal of the Union troops from Hill's Point, withdrew his gunboats from the Nansemond River but made a deal with Getty that he would return the gunboats if pickets could be sent to Hill's Point.
Split into simpler sentences: Lamson, discouraged at the removal of the Union troops from Hill's Point, withdraws his gunboats from the Nansemond River. Lamson made a deal with Getty that he would return the gunboats if pickets could be sent to Hill's Point.