Text-fig. 2. Geological setting of the studied sites. a: Stratigraphic position of the Mospyne Formation in the Carboniferous succession of the Donets Basin. b: Stratigraphic position of the studied locality of ammonoids (numbers in circles to the right of the lithological column). c–f: Some studied localities, c – stratigraphic level with ammonoids No. 8, d – stratigraphic level No. 4, e – stratigraphic level No. 3, f – part of the section of the Mospyne Formation in Sukha Ravine and the position of stratigraphic levels with ammonoids. Abbreviations: Tour. – Tournaisian, Serpukhov. – Serpukhovian, Kasimov. – Kasimovian. in Late Bashkirian Ammonoids From The Mospyne Formation Of The Donets Basin, Ukraine