In I.M. Andreiev's Russia's Catacomb Saints, translated into English by Fr. Seraphim Rose, there is an addendum which contains encyclicals written by a catacomb bishop, during the 1960's/70's Soviet Era, by the name of "Met. Theodosius."
Does anyone know who this figure was/is, and which Catacomb group in Russia represents his synod or has a number of his spiritual descendants?