In the domestic literature the classification of coal-bearing formations was discussed more than once and in different variants. In 1959 we published a new, more detailed, genetic classification of coal-bearing formations. Е. О. Pogrebitsky, critically estimating it, classifies coal-bearing formations differently ...

Any work devoted to the analysis of complex and debatable issues of coal formation is of great interest. Especially valuable are the works in which researchers, despite more or less established ideas, try to bring new insights into the understanding of the complex and diverse process of coal formation. One of the main regularities of coal formation, clearly revealed by lithological studies over the past two decades in the main domestic coal basins, is the establishment of a paragenetic relationship between coal seams and their host rocks. This relationship is best revealed in the phenomenon of rhythmicity of coal-bearing strata, the study of which clearly reveals the interaction of geotectonic (movements of the Earth's crust) and facies (relief, climate, vegetation, etc.) factors of sedimentation and coal formation.

In order to compare lithological methods of studying coal-bearing deposits, the article considers the main theoretical basis of the facial-geotectonic method developed by the author, which is essentially different from the facial-cyclic and facial-geotectonic methods, and raises the question of merging the facial-cyclic and facial-geotectonic methods. The practical application of the proposed lithologic methods in geological exploration is evaluated.

The Leningrad Mining Institute, the entire geological community of our country and especially coal geologists suffered a great loss - on January 9, 1957, at the 72nd year of his life Yuri Apollonovich Zhemchuzhnikov - the oldest professor of the Institute, corresponding member of the USSR Academy of Sciences - died. The glorious creative life path of the greatest scientist, talented teacher, who gave all his strength and abilities to serve our Motherland, was interrupted. Yuri A. Zhemchuzhnikov was born on April 26, 1885 in Samara. In 1902 he graduated from a real school in St. Petersburg and in 1903 entered the Mining Institute. He was expelled from the institute in 1904 for participation in student strikes. Returning then to the institute in 1908, he graduated in 1915 with an exploration specialty.