Based on the study of the systematic composition, morphological features, habitat conditions, the time of appearance and disappearance of echinoids in the Cenomanian-Santonian time in the Lesser Caucasus, the Cenomanian-Santonian stage is distinguished, including the Cenomanian, Turonian, Coniacian and Santonian phases. It has been established that each distinguished phase corresponds to complex moments, differing from each other in their evolutionary changes of a particular taxon during a certain geological time, that is, appearance and disappearance, lush reproduction and fre-quency of appearance in sections.