Original sentence: Two historic lighthouses are present on the island: Block Island North Light, on the northern tip of the island (established in 1829, current lighthouse was built in 1868), and Block Island Southeast Light, on the southeast side of the island (built in 1875)
Edited sentence: Two historic lighthouses are present on the island: Block Island North Light, on the northern tip of the island, and Block Island Southeast Light, on the southeast side of the island