The Kalodiki fen is a 2-km2 mire in a small basin within a tectonic depression in Epirus, western Greece. Since the last glaciation the basin has been occupied by a freshwater lake and has accumulated as much as 9 m of peat, which continues to form today. A 10-cm-thick, light-brown to olive fine sandy layer appears in cores at depths ranging from 2.9 to 5.7 m. The sand fraction of this layer consists mostly of pumice fragments and brown and colorless glass shards with similar major-element compositions, and it also contains crystal fragments of feldspars (mainly sanidine), ferromagnesian minerals, and probably sphene and apatite. The colorless glass has an index of refraction 1.519 ± 0.002. A sample of the overlying peat layer gave a minimum radiocarbon age of about 31,800 ± 1200 yr B.P. for the deposition of the tephra. The likely age of the tephra, its index of refraction, and its mineralogical and chemical characteristics display strong similarities to tephra from the Campanian province of Italy. Mineralogically similar tephra layers have also been reported from a peat deposit at Philippi, in northeastern Greece.