In the literature on the geology of Altai there is a widespread opinion about the wide development of volcanogenic strata of porphyritic composition crowning the Upper Paleozoic section of the Kalba Ridge. This opinion is based on the works of G. I. Sokratov, who studied the Upper Paleozoic sediments of this area for a number of years. According to G. I. Sokratov, the geological structure of the Southern Kalba, where the section of the above-mentioned formations is most fully represented, includes Upper Vise-Namur (Kokpektin Formation), Middle Carboniferous (Bukonya Formation), Middle-Upper Carboniferous (Maityubinsk Formation) and Permian (Daubai Formation) sediments. The age of the Kokpektin Formation is proved by faunal finds. The Bukonya Formation is characterized by Middle Carboniferous flora. The age of the Maityubinsk Formation was determined on the basis of findings of freshwater peledipods similar to those described from the Alykaevskaya Subformation of Kuzbass. The Daubaiskaya Formation is conditionally attributed to the Permian, since no organic remains were found in it, and its relationships with the Maityubinskaya Formation have not been established anywhere. Porphyritic covers are identified at the base of the Maityubinsk Formation (C2-C3), as well as in the uppermost parts of this formation in the Kulambai Mountains. The main mass of the Kalba volcanogenic formations is allocated to the Daubai Formation (P).