''The Ruined Abbey'' At The Dell To North Of Goodwood House With Attached Tunnel System Including Underground Chamber To North-East And Northern And Southern Tunnel Entrances

"The Ruined Abbey" at the Dell, located to the north of Goodwood House, features an attached tunnel system that includes an underground chamber to the north-east, along with northern and southern tunnel entrances. This garden feature was created around 1730 for the second Duke of Richmond. The structure is made of coursed stone, brick, and flint, and was partly covered in ivy at the time of inspection on February 3, 2000.

The "Ruined Abbey" consists of a round-arched tunnel entrance flanked by narrow stone piers with niches and re-used medieval crocketed canopies, which are partly collapsed. The tunnel itself is stone-lined but currently blocked. It extends eastward to connect with a north-south tunnel that features an underground circular chamber near its northern end, along with round-arched entrances at both ends. The southern entrance is set within a flint retaining wall, and the tunnel is lined with flint, transitioning to brick after approximately 11 meters, with a partly collapsed flint cell on its eastern side after about 18 meters. The northern entrance is situated in a retaining wall made of red-brown brick in English bond, complete with brick plinths and imposts, and a late 20th-century iron gate; stone steps lead up on either side.

The underground chamber is lined with brick and includes a blocked central circular roof-light, nine arched stone niches along the walls, and another bricked-up entrance. "The Ruined Abbey" is one of several structures built around the bowl of a man-made amphitheatre, all constructed for the second Duke of Richmond as part of his famous menagerie, where birds and animals were housed and buried within the tunnel system and its associated chambers.