Thin beds of lacustrine carbonate are locally exposed between linear dunes of the sand sea. Ward (1984) has mapped the occurrence of these beds, distinguishing between those of probable Tertiary-age, which are weathered out of the Tsondab Sandstone. and those which are related to the Quaternary-age Sossus Sand Formation of the present Sand Sea. Ward (1984) names the younger carbonate the Khommabes Carbonate Member (of the Sossus Sand Formation) after the type locality at Khommabes, which lies just south of the Kuiseb River near Gobabeb. Keywords: Namibia, Namib Desert, Kuiseb River, Tsondab River, Tsauchab River, Khommabes, Gobabeb, desert geology, geomorphology, desert environment, microfossil deposits, diatom flora, palaeoecology, interdune pans.