sentences:  In the early 1950s Sokolov joined a group of geologists tasked with the analysis of recent deep boring samples.Sokolov discovered what he believed was a hitherto unknown geographical layer preceding the Cambrian, which he called "Vend" ("Vendian Period").The name "Vend" appeared in his papers from 1950; in 1952 academician Alexander Vinogradov endorsed Sokolov's theory and "Vend" appeared on Soviet geological charts as an independent period.