One of the most important and interesting geological questions awaiting solution is that of the origin of continental shelves and slopes. Just as for other geological features, more than a single origin is involved for different areas or for different times. Data on structure, composition, and topography provide the clues for interpretation of geological history and thus of origin, but such clues are presently so incomplete that interpretations are uncertain. Common to many areas is the presence of a downwarped basement under the slope and (or) a topographic depression beyond the slope--but is this cause or effect? Also common is the composition: marine sediment--but what can we infer about the precise environment of deposition of these sediments? Are they neritic under t e inner part of the shelves and bathyal beneath the slopes? How important are turbidites for the continental rise beyond? How similar are the Mesozoic and Tertiary sediments to those of the Pleistocene and Recent? The present topography is reasonably well known--but is it similar to ancient topography? In many areas the present shelf has been shaped by processes unique to the Pleistocene--does this mean that continental shelves did not exist before the Pleistocene? New data will be presented by the different speakers, all of whom have been active in field studies. We, perhaps, will find that a comparison of the results of their field work in large, but widely separated, areas will provide a much needed fresh approach to the question of the origin of continental shelves and slopes.

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