Deposits containing the plant fossils studied and developed in the localities Troisdorf-Altenrath, Siegburg-Stallberg and Hennef-Söven belong stratigraphically to the siliciclastic facies of the Underlying Strata of the Seven Mountains (Siebengebirge), which is interpreted as a marginal facies of the Cologne (Köln) formation correlated with the clay 06 of the local lithostratigraphical column. Chronostratigraphically they are assigned to the late Oligocene (Chattian) on account of the correlation with the fauna recovered in the contemporary site at Rott.
These coarse-grained to silt and clayey deposits originated in coastal and slope-wash areas within fluviatile environments of variable deposition energy. Fine-grained leaf-bearing layers accumulated in temporarily flooded levees.
Remains of Taxodium dubium, Eotrigonobalanus furcinervis, Populus germanica and Daphnogene cinnamomifolia dominated among the recovered fossil species. General aspects of this plant assemblage correspond, together with sedimentary settings, to the riparian forest vegetation with mesophytic elements.