Large detailed map of Suriname
The ruins are suposed to be in the mountainous areas at the end of the rivers that connect to the sea.
Perhaps there is more information on this.
A5735 Goeje, C. H. de 53.0000 SR 1908 Verslag der Toemak Hoemak expeditie Account of the Tumuc-Humac expedition. Tijdschr Ned Aar Genoot 25: 945-1168. 54,55 A