Geological Survey (U.S.) / Marius Robinson Campbell / Charles Butts / Ralph Arnold / Nevin Melancthon Fenneman / Hoyt Stoddard Gale / Willis Thomas Lee / Frank Charles Schrader / William Clifton Phalen / Cassius Asa Fisher / George Hall Ashley / Frederick B. Peck / George Burr Richardson / Joseph Alexander Taff / Nelson Horatio Darton / Arthur Gray Leonard / Arthur Clifford Veatch |