Ten prehistoric Comb Ceramic vessels found near Kotka have been studied with the aid of AAS and diatom analysis.Correspondence between stylistic and decorative groupings show that the variation in the elements determined by AAS is apparently due to the coarse sand temper added to the clay during the actual manufacture of the Shoes vessels.The composition of the Pit and Comb Ware vessel differs considerably from the others, the ornamentation suggesting East Karelian provenience.The diatom flora in the clay material Watches of the vessels corresponds to the stylistic classification.
The raw material was apparently either glacial or fresh water clay, whose technical properties correspond to those of clay in modern tile production.