After completing a geology degree at Yale and serving as a volunteer for Whitney's Geological Survey of California, Clarence King organized and directed the Fortieth Parallel Survey [1867-72] from the Sierra Nevada (SN) across the Rocky Mts., topographically and geologically mapping 87,000 sq. mi. His interpretations presented in 'Systematic Geology' [1878] and later papers reflect both his training at Yale, strongly influenced by J. D. Dana, and personal field and laboratory observations. Some of these interpretations have proven to be incorrect, but when viewed in context of his times they reflect superb critical thinking by King. For example, his requirement of a western sediment source and uniform gradual subsidence due to loading in the Great Basin (GB) during the Paleozoic reflected a consensus that granitic and most metamorphic rocks were Archean, and that facies indicated a Paleozoic strand line east of SN. Post-Jurassic catastrophic tectonism resulted in sudden depression of the SN Archean land and uplift of GB Paleozoics, accompanied by extensive folding reflecting chiefly east-west crustal shortening, with deformation lessening eastward and fold locations strongly influenced by a high relief, largely buried Archean topography. Complex high angle Tertiary faulting accompanying catastrophic rhyolitic volcanism resulted in dislocation of old folds, and ranges were broken into irregular blocks with thousands of feet of relative vertical displacement. Tertiary basalts succeded rhyolites, and, finally, extensive pluvial lakes formed contemporaneously with extensive alpine glaciation. King rejected strict Lyellian uniformitarianism and related Darwinian evolution to episodes of selection pressure engendered by natural catastrophes, for which he found evidence in his field area. King's [1893] refinement [to 24 my] of Kelvin's earth age estimate from terrestrial refrigeration reinforced his conception that inadequate time existed to explain the Fortieth Parallel geologic record by radical uniformitarianism, and that higher energy, accelerated geologic processes best accounted for episodes of uplift/subsidence, faulting, volcanism and landscape degradation. King thus stands out as an early 'actualist', in some ways quite modern in his approach to event stratigraphy.