based upon settling rates, though there is considerable mixing of sizes. Most of the Halimeda fragments settled first to form layer C, with some living green Halimeda included; the latter has not yet decomposed and still retaining its green color. Coarse sand, followed by progressively finer sand and silt-sized particles settled later, followed by the silt and claysized particles composing the mud. The latter is quite fine (about 40% of the particles by weight are less than two microns in diameter, and 35% between 20 and two microns), cream colored, and with a typical fetid odor, The mud contains the only evident non-calcareous © material in the sediments -dark streaks and occasional small, crumbly, dark-brown Jumps which chemical tests indicate to be nearly pure carbon. The latter may represent the tissues of fish, or possibly oil, carbonized by the intense heat of the explosion. This carbonized material makes up less than 1% of the sediment. The mud also contains about 0.1% by weight of iron, presumably from the target ships. ...The animals. mud is pitted Holothurians (sea the bottom in abundance.... by the borings cucumbers) of marine are living on The thickness of the three top layers of sediment in the target area varies greatly, as shown in Figure C-2 and in the cross-sections of Figure C-3. In Figure C-3, the thicknesses of the various layers of sediment are plotted against distance from the position of LSM-60, with no attempt made to show the topography of the bottom. Two sections are shown; one running NESW, the other E-W. Note that the layer is 5 ft. 3 in. thick below the LSM-60 location, and reaches a maximum of 8 ft. in thickness 125 yd. to the southwest in core No. 33. Also, the longest core taken (No. 4: 10 ft. in length) failed to penetrate the second layer (silt and sand) near the center of the target area. Near the edge of the mud area, on the other hand, the second and third layers frequently are missing (as in core No. 5), and a very thin layer of mud, a fraction of an inch in thickness, rests directly on the original bottom sediment (Halimeda debris). Although the bottom was Stirred explosion to a distance of 1,000 to 1,500 C-3), the intense disturbance was limited of about 300 yd. Moreover, the center of 5000006 - C-5 up by the yd. (Figure to a radius intensity is