In the middle Volgian sandstones of southeastern Western Siberia, monospecies coquinas composed of the shells of Meleagrinella lata were previously considered as a reference level (beds with M. lata) of the upper sublittoral facies. The study of materials collected from the Naknek Formation in the Talkeetna Mountains (southern Alaska) showed that there are numerous slabs of predominantly monospecific coquinas composed of different-sized shells of Meleagrinella lata. Sometimes these coquinas contain shells of Buchia mosquensis. Meleagrinella coquinas commonly come from the Upper Naknek Formation, which corresponds to the B. mosquensis Zone and was formed on a shallow sea shelf. It can be assumed that these coquinas correspond to the middle Volgian reference coquina level of the upper sublittoral facies in southeastern Western Siberia.