Alleghanian orogeny Province must have been even more intense; however, there is little evidence preserved. Rocks of Mississippian, Pennsylvanian, and Permian age are missing along the Eastern Seaboard. The mountains formed by the Alleghanian orogeny were once rugged and high, but in our time are now eroded into only a small remnant: the heavily-eroded hills of the Piedmont. Sediments that were carried eastward formed the coastal plain and part of the continental shelf. Thus, the coastal plain and Piedmont are largely the byproducts of erosion that took place from 150+ million years ago to the present. Sediments that were carried westward formed
Malagasy orogeny Malagasy orogeny Malagasy orogeny is the name given to the Ediacaran to Cambrian orogeny that resulted as India collided with the already amalgamated African continent that consisted of Azania and the Congo-Tanzania-Bangweulu Block. The orogeny affected the parts of the East African Orogen that are now found in southern India, Madagascar and central Arabia. The term "Malagasy orogeny" was introduced by for the orogenisis between India and a series of Gondwanan cratonic blocks in present-day Africa (Congo/Tanzania/Bangweulu/Azania). In their reconstruction, India collided with Australia/Mawson in the Kuunga orogeny before the formation of Gondwana. They identified the Betsimisaraka suture in eastern