PLATESPLATEFOLLOWING PAGE1.Physiographic diagram: Atlantic Ocean, Sheet 1(In separate tube)2.Preliminary chart of Hudson Submarine Canyon203.Representative PDR records from continental rise of northeastern United States324.PDR records from continental slope and Blake Plateau325.PDR records from outer ridge east of the Blake Plateau and from the Blake-Bahama Abyssal Plain326.PDR record of outer ridge showing sub-bottom horizon327.Tracings of PDR records across continental slope and part of the Blake Plateau368.PDR records European continental rise and Biscay Abyssal Plain389.Representative PDR records of continental margin and abyssal floor southwest of Canary Islands3810.PDR record of abyssal hills, southeast of Bermuda Rise3811.Ocean bottom photographs of the continental margin and ocean basin floor3812.PDR record of Biscay Abyssal Plain5213.PDR records of Madeira Abyssal Plain and the Madeira Rise5214.PDR records of Mid-Ocean Canyon No. 2 and canyons at Vema Gap5815.Ocean-bottom photographs of seamounts5816.Representative PDR records from Bermuda Rise7817.PDR record, Bermuda Scarp Zone7818.PDR record, Upper Step Mid-Atlantic Ridge7819.Ocean-bottom photographs; Mid-Atlantic Ridge7820.Physiographic provinces, Atlantic Ocean12221.Control chart12222.Six trans-Atlantic topographic profiles12223.Index chart showing locations of profiles of Plates 24, 25, 26 and Figure 4512224.Thirty-four profiles of the continental margin: western North Atlantic12225.Twenty-three profiles of the continental margin of Europe and Africa12226.Crustal structure and continental-margin provinces12227.Five topographic profiles, western North Atlantic12228.Distribution of deep-sea sands in relation to physiographic provinces12229.Earthquake epicenters, North Atlantic12230.Location of PDR records and bottom photographs reproduced as illustrations.122FIGURESFIGUREPAGE1.Method of preparation of physiographic diagram42.Precision depth recorder (PDR) sounding lines obtained by research vessels63.Good, but nonprecision sounding lines obtained by research vessels74.Major basins of the North Atlantic, after Wüst (1940)125.Sound-velocity corrections for echo soundings136.Conversion diagram for degrees, per cent grade, feet per statute mile, and gradient147.Gradients from 1:5 to 1:8000 shown at 40:1 vertical exaggeration158.Outline of submarine topography159.Major morphologic divisions: North Atlantic Ocean1610.Three categories of continental-margin provinces1711.Two east-west profiles of Southeast Newfoundland Ridge2212.Laurentian Channel2313.Eastern Channel, Gulf of Maine2314.Submarine canyons off the Scotian Shelf2415.Continental-margin provinces: Type profile off northeastern United States2616.Tracings of PDR records of continental and insular slopes2817.Cross sections of Hudson Submarine Canyon3218.Tracing of PDR record of Blake Escarpment3419.Continental-margin provinces: Type profiles off northwest Africa4020.Georges Bank canyons4421.Two projected profiles of Georges Bank canyons4522.Geologic section at Cape Hatteras, Virginia4623.Correlation of structural benches off northeast United States4824.Geologic section: Western Europe based on refraction measurements4925.Index chart, location of abyssal hill profiles illustrated in Figures 26 and 276226.Eleven profiles, Abyssal Hills Province, western Atlantic6227.Eight profiles, Abyssal Hills Province, eastern Atlantic6328.Tracing of PDR record, abyssal hills, southeast of Bermuda Rise6429.Northwest Atlantic Mid-Ocean Canyon6730.Eight east-west profiles showing Northwest Atlantic Mid-Ocean Canyon6831.Forty-eight cross sections of Northwest Atlantic Mid-Ocean Canyon6932.Long profile of Northwest Atlantic Mid-Ocean Canyon7033.Tracing of PDR record across Theta Gap7334.Natural scale profile, Kelvin Seamounts7735.Crustal sections in various physiographic provinces, determined by seismic-refraction measurements8136.Index to natural-scale Mid-Atlantic Ridge profiles reproduced in Figures 37-418437.Natural-scale Mid-Atlantic Ridge profile 1A8538.Natural-scale Mid-Atlantic Ridge profile 1B8639.Natural-scale Mid-Atlantic Ridge profile 1C8740.Natural-scale Mid-Atlantic Ridge profile 2A8841.Natural-scale Mid-Atlantic Ridge profile 2B8942.Type profile, provinces of the Mid-Atlantic Ridge9043.Tracing of PDR record, Rift Valley, Rift Mountains, High Fractured Plateau, and Upper Step9144.Tracing of PDR record, Western Rift Mountains9245.Twenty-six rift valley profiles, Mid-Atlantic Ridge9346.Five representative profiles, crest and western flank of Mid-Atlantic Ridge9447.Axial profile of the Mid-Atlantic Ridge9648.Profile of total magnetic intensity and topography, Mid-Atlantic Ridge10149.Physiographic provinces and trans-Atlantic structure102TABLESTABLEPAGE1.Characteristics of continental rise, northeastern United States272.Characteristics of continental rise, northwest Africa413.Depths of prominent continental-shelf terraces42