Complex sentence: Unfortunately, most of the Cornwall ironworks fell out of the Grubb family's hands by 1802; but later generations, starting with Peter Jr.'s son Henry Bates Grubb, built on the remaining holdings with great success.
Split into simpler sentences: Unfortunately, most of the Cornwall ironworks fell out of the Grubb family's hands by 1802. But later generations, starting with Peter Jr.'s son Henry Bates Grubb, built on the remaining holdings with great success.