Wide areas, giving rise to oceanic depressions and leaving the continents protuberant; the other, folding along comparatively narrow belts, giving rise to mountain ranges.
Upon the denuded edges of the Scotland beds lies the Oceanic series.
The Oceanic series is generally overlaid directly, and unconformably, by coral limestones; but at Bissex Hill, at the base of the coral limestones, and resting unconformably upon the Oceanic series, there is a Globigerina marl.
The honour of first sounding really oceanic depths belongs to " Egeria," " Waterwitch," " Dart," " Penguin," " Stork," Sir James Clark Ross, who made some excellent measurements and " Investigator."
Large angles of slope may, however, occur on the flanks of oceanic islands and the continental borders.