Lacus Temporis (aka Mare Horologii)
Lat: 45.9°N, Long: 58.4°E, Diam: 117 km, Depth: km, Rükl: 15
A location in or near Lacus Temporis seems to be the centre of a basin which is unofficially known as U4, according to the nearside map in the page Lunar Basins List.
"Lake of Time".
Once called Mare Horologii by J.P.H.Fauth and E.Debes (see at Carrington in THE MOON by H.P.Wilkins and P.Moore, page 209, Section 13).