The South Dock is a large rectangular tidal basin with walls of massive squared stone blocks and with massive stone slab capstones; it was built 1839-41. The entrance is at the north-west corner, and a slipway extends from the south-west corner along the inside of the outer quay. There were extensive slate stacking yards on the north-east and south-east quays, served by narrow gauge railways. The dock is now a marina and the wharves have been redeveloped for housing.
(Information from CADW listing description).