Complex sentence: Ferrand was the first to use the term Vercors in its contemporary sense, but the geographers Raoul Blanchard and Jules Blache were responsible for popularising it in the late 1920s and early 1930s.
Split into simpler sentences: Ferrand was the first to use the term "Vercors" in its contemporary sense. The geographers Raoul Blanchard and Jules Blache, popularised the term in the late 1920s and early 1930s.