Orogeny process whereby new mountains and other land-forms were thrust up, or else there would eventually be no land; he suggested that marine fossils in mountainsides must once have been at the sea-floor. Orogeny was used by Amanz Gressly (1840) and Jules Thurmann (1854) as "orogenic" in terms of the creation of mountain elevations, as the term "mountain building" was still used to describe the processes. Elie de Beaumont (1852) used the evocative "Jaws of a Vise" theory to explain orogeny, but was more concerned with the height rather than the implicit structures created by and contained in orogenic belts. His
Acadian orogeny the central to southern Appalachians, evidence for the Acadian orogeny is poor, and is found primarily in the plutonism of the Blue Ridge and metamorphism of the Cat Square terrane. The Acadian orogeny experienced at least three major phases of deformation, and in places, unconformities were recognized. These phases were called tectophases, and represented the sequence of collisions that occurred from the Avalonian terranes accreting to Laurentia. As a result of these tectophases, deltas developed on the adjacent parts of the stable craton, eastern margin of Laurentia. These deltas are described as foreland-basin, delta-complex clastic wedges, which are responsible for