Complex sentence: Unlike the cave in Carden Park, no material dating to the 18th century has been discovered at Bickerton, and the name "Mad Allen's Hole" originated in the late 19th century, when the cave was occupied by an eccentric known as Mad Allen.
Split into simpler sentences: Unlike the cave in Carden Park, no material dating to the 18th century has been discovered here. The name "Mad Allen's Hole" originated in the late 19th century, when the cave was occupied by an eccentric known as Mad Allen.