Abstract Clarence Edward Dutton (1841–1912), a Yale University graduate, served in the Civil War and, as a captain in the United States Army, was detailed for duty with John Wesley Powell’s US Geographical and Geological Survey of the Rocky Mountain Region and, later, the US Geological Survey. He spent 10 years in geological research in the Colorado Plateau region, studying its geomorphological and stratigraphic evolution, and coined the term ‘isostasy’. His monograph Tertiary History of the Grand Cañon District is renowned for its particular charm, with sublime landscape descriptions and superb illustrations. Dutton later undertook studies in volcanic geology in Hawaii, the Cascades and on the Colorado Plateau. Dutton studied the effects of the catastrophic Charleston earthquake of 31 August 1886 and later engaged in irrigation research in the American West. Dutton critically reviewed many major geological concepts, including the causes of volcanism, earthquakes and, especially, orogeny. His pioneering work on stratigraphy, geomorphology, isostasy and seismology place him at the forefront of nineteenth century researchers and reflects his ability to generalize from field observations and formulate principles that constitute explanations of the observed facts.

Over one hundred years ago, J.S. Diller (1902) published his classic work, Topographic Development of the Klamath Mountains, in which he proposed that a regional lowland erosion surface, the “Klamath peneplain,” formed in northwestern California during the late Miocene. W.P. Irwin's (1997) Preliminary Map of Selected Post-Nevadan Geologic Features of the Klamath Mountains and Adjacent Areas clearly delineates the extent of this erosion surface and provides detailed mapping and age determinations for overlap deposits in both the Klamath and Coast Range provinces. Among these deposits, basal late Miocene Wildcat Group, Saint George Formation, and Wimer Formation sediments are littoral. Rapid submergence of northwestern California to bathyal depths occurred, following initiation of Wildcat–Saint George–Wimer sedimentation. By 5 Ma, the Klamath peneplain was at sea level, based upon Wimer Formation overlap. A 40 Ar/ 39 Ar laser probe analysis of detrital micas indicates that Wildcat Group marine sediments are, in part, derived from the Idaho batholith. Sediment progradation and shoaling over a wide coastal shelf, onset of deposition of locally derived fluvial sediments in the Coast Ranges, and regional uplift during the middle Pleistocene may relate to the decreasing age of the subducting oceanic plate, decreasing dip angle of subduction, translation of the Sierra Nevada microplate northwestward as it impinges upon the Klamath block, and/or migration of the Blanco fracture zone northward along the continental margin.