Two identical stones on the north and south shores of Lantau Island mark the points at which the sea boundary (Pre-1997) with China touches the Island. The stones are granite, pointed on top, and standing on stone bases. A carved inscription on one of the faces of each base states that the stones were fixed in position by Lieutenant-Commander F.M. Leake, R.N. and officers of H.M.S. Bramble in 1902 in the longitude 113°52'0". The opposite face bears a corresponding inscription in Chinese. Both stones are marked as obelisks on ordnance maps.
The text differs slightly on the two stones. The full text on the Northern Obelisk on its south face of the base is as follows:
1902
This stone is in longitude
113°52'0" fixed by Lieut and
Comdr F.M. Leake, R.N. and the
officers of H.M.S. "Bramble".
From here the boundary line
extends due North until it meets
the parallel of the southern
extremity of the Nam -Tau
Peninsula. Southward the
boundary follows the western
shore of Lantao Island.
On the west face of the base:
This stone is placed 380
feet above H.W. mark for the
purpose of protecting it from
possible inroads of the sea.
Source: In Search of the Past: A Guide to the Antiquities of Hong Kong. See South Lantau Obelisk here The obelisk marking the eastern longitude of Hong Kong can be read here