challenge: What was the main point of contention between Roderick Murchison and Henry De la Beche during the Great Devonian Controversy?
  
  A. The age of the Greywacke stratum in North Devon, England
  B. The placement of Carboniferous fossils within the Greywacke stratum
  C. The validity of using fossils to date rocks
  D. The classification of the Old Red Sandstone formation
  Answer: 