Sediiaent types also changed from rock flour at the western station to 

 glacial till at the bottom of the mids trait core and throughout the 

 short core obtained off D'Hrville Island, the cores being taken in 

 590, 8hO, and 223' meters of water, respectively. Penetration was 

 good except at the D'Urville Island station where only 6 inches of 

 sediment was obtained; the other two cores were 2ii inches in length. 

 Color of the sed-ttaent ranged from light olive gray in the two western 

 stations to olive gray at D'Urville Island, Sphericity of particles 

 was low moderate to high, roundness was decidedly angular with particles 

 at the bottom being very angular in all cores. Surface texture of 

 particles was mainly rough polished in the mineral grains and smooth 

 and dull in the rock fragments. At the bottom of the Deception Island 

 core and at the top of the midstrait sample the particles were pitted. 



Particles of sand size or larger showed a decided increase eastward, 

 being on an average h percent of the sati^jle at Deception Island, ih 

 percent at the midstrait core, and $1 percent off D'Urville Island, 

 Clay sized particles were 38 percent, lH percent, and 21 percent at 

 the three stations from west to east. The dominant material at the 

 top of the Deception Island core was volcanic glass, diatoms were 

 dominant at the bottom of the core. The dominant material at the 

 top of the midstrait core was volcanic ash, scoria was dominant at 

 the bottom. Volcanic ash was again dominant off D'Urville Island, 

 Secondary minerals at top and bottom were noted as follows: at 

 Deception Island, diatoms and quartz j midstrait, quartz and diatoms j 

 and at D'Urville Island, quartz. Feldspar, quartz, diatoms, and 

 volcanic ash were also noted at locations where they were not dominant 

 or secondary, while at the bottom of the midstrait core there were 

 some acid minerals noted, although in small amounts. Sponge spicules 

 and di-atoras were found at the top of the midstrait and D'Urville cores 

 and the bottom of all three cores. Arenaceous foraminifera were foxmd 

 at the top of the Deception Island qore and the bottom of the midstrait 

 core. Calcareous foraminifera v;ere present in both the top and bottom 

 of the corR at Deception Island and at the top of the midstrait core, 

 Radiolarians were found only at the top of the cores taken at the two 

 western stations, A heavy liquid separation made on the bottom sample 

 of the Deception Island core gave the following results; light weight 

 sand fraction 66 percent; heavy sand fraction 3U percent; magnetic 

 light sand fraction h percent; and magnetic teavy sand fraction 8 

 percent. Here, as at Peter I Island, the magnetic separation figures 

 are very high. The median diameter of the particles in fi units in the 

 top sections of cores was as follows; Deception Island 6.82, mid- 

 strait 6,55, and D'Urville Island 3,90. The median diametov at the 

 bottom of the two western cores was 6,78 and 7.10. 



Organic carbon content was higher in the Bransfield Strait sediments 

 than in any of the other areas investigated on the cruise, averaging 



^2 



