The sedimentary framework of selected continental margins of North and Central America has been investigated by means of non-explosive, continuous-reflection seismic systems. These records have been interpreted in the light of present knowledge of distribution of sedimentary facies and the processes of transgression and regression on modern continental shelves.

As a result of these studies, it is concluded that there is no typical continental margin. Fundamental differences exist in regional tectonism, rates of supply of sediments, and oceanographic agents of transportation, deposition, and erosion. Predominantly tectonic-erosional versus depositional types can be recognized, but are not necessarily related by evolutionary sequence. Submerged Pleistocene deltas are important in shaping present continental shelves and slopes. All types of shelves and slopes recognized today, existed prior to the Quaternary, but without the depth uniformity and abruptness of shelf break.

End_of_Article - Last_Page 364------------