Complex sentence: Upon the death of James R. Keene in 1913, the farm was taken over by his son, Foxhall P. Keene who continued the operation on a slightly reduced basis but who sold it in the 1920s to fellow New Yorker, David Look.
Split into simpler sentences: Upon the death of James R. Keene in 1913, the farm was taken over by his son Foxhall P. Keene. He continued the operation on a slightly reduced basis but sold it in the 1920s to fellow New Yorker, David Look.