Simplify the following text for a Grade 10 native English-speaking person.
Original: The Ediacaran Period overlaps , but is shorter than the Vendian Period , a name that was earlier , in 1952 , proposed by Russian geologist and paleontologist Boris Sokolov .
Simplified: The Ediacaran period was previously called the Vendian period . The Vendian period was proposed in 1952 by Russian geologist\/paleontologist Boris Sokolov .