FIGURE 1. SUB-BOTTOM ECHOES ON RECORD FROM SOUTHERN BERMUDA RISE FIGURE 2. MID-OCEAN CANYON NO. 2 FIGURE 3. MID-OCEAN CANYON IN HATTERAS ABYSSAL PLAIN, WEST OF VEMA GAP PDR RECORDS OF MID-OCEAN CANYON NO. 2 AND CANYONS AT VEMA GAP Depth in fathoms.] [Illustration: Heezen _et al._, PL. 15 Area of each photograph is about 6 by 8 feet. PLATE 15.--OCEAN-BOTTOM PHOTOGRAPHS OF SEAMOUNTS FIGURE 1. (Station V4-12, photo 16) Depth 700 fathoms, location 35° 12´N., 15° 18´W., on seamount of the Horseshoe Group. Note bioclastic debris lodged in depressions on the rocky bottom. Photographs shown in Figures 1, 2, and 3 are no more than a few hundred feet apart. FIGURE 2. (Station V4-12, photo 10) Depth 700 fathoms, location 35° 12´N., 15° 18´W. Rippled sandy bottom. FIGURE 3. (Station V4-12, photo 7) Depth 710 fathoms, location same as Figures 1 and 2. Note current ripple marks. The photograph indicates an appreciable current from left to right. FIGURE 4. (Station V4-16, photo 19) Depth 1100 fathoms, location 35° 07´N., 13° 04´W., on the side of Ampere Seamount. Note winnow row of dark and light gravel-sized detritus which resembles similar material on the Rift Mountains shown in Figure 1 of Plate 19. FIGURE 5. (Station V4-18, photo 26) Depth 75 fathoms, location 35° 10´N., 12° 55´W., near the top of Ampere Seamount. FIGURE 6. (Station V4-14, photo 47) Depth 1100 fathoms, location 35° 12´N., 15° 22´W. on same seamount as Figures 1-3. Bottom appears to consist of light-colored sediment thinly veiled by dark coarser sediment. The white polka dots appear to represent piles of the underlying light sediment brought to the surface by burrowers. Positions of stations shown on PLATE 30] BLAKE-BAHAMA ABYSSAL PLAIN: The Blake-Bahama Basin is a long narrow basin between the great Blake Escarpment and calcareous Bahama Island banks on the west and the outer ridge on the east. A narrow abyssal plain 20 to 70 miles wide spreads out from the base of the escarpment (Pl. 5, fig. 3). The plain is shallowest and widest just east of the Northeast Providence Channel and deepens and narrows toward its northern and southern ends. Sediment cores taken 60 miles off the mouth of Northeast Providence Channel contained graded beds of calcareous sand a few meters thick (Ericson _et al._, 1952). The material was obviously derived from the Bahamas, presumably through the action of turbidity currents running out through the Providence Channels, the southern entrance of Exuma Sound, and the numerous submarine canyons which dissect the slopes off the islands. The depth of the plain ranges from 2600 to 2750 fathoms, and its area is about 7000 square miles.