Who is Captain Clarence E Dutton from Beyond the Hundredth Meridian: John Wesley Powell and the Second Opening of the West and what is their importance?

Captain Clarence E. Dutton is described as being, much like Gilbert, an extension of Powell. He took on the projects Powell laid the foundation for, and brought them forward using his own personality and traits. Dutton continued his career with Powell, and his is credited as havng made a substantial contribution to the West.