A fatal attack by the shark Carcharhinus galapagensis at St. Thomas, Virgin Islands : Randall J.E., 1963. Caribb. J. Sci., 3 (4): 201205

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Oceanographic Abstracts 1071 currents as the driving agency, the proposed model is basically akin to convection currents insofar as the driving energy in the last instance is the potential thermal energy of the globe. In conventional convection, thermal global energy is transferred to mechanical work through the process of continuous expansion and contraction during heating and cooling of a homogeneous medium, and consequent buoyancy in the field of gravity. In the proposed model it is a matter of discontinuous, and also much larger, expansion and contraction during melting and crystallization, with consequent buoyant tendency of the melt and sinking tendency of the crystalline phases. Absorp- tion of heat of melting at depth and release of heat of crystallization at levels close to the surface make this kind of heterogeneous '" convection" a much more efficient "coo le r " of the earth than homo- geneous convection. Since the conventional current works in a homogeneous plastic or visco-elastic medium, whereas the working material in the proposed model is a heterogeneous mixture of solids and melts, it is quite clear that considerable difference must be expected in the movement pattern at depth as well as the surficial reflection of the movement on the earth's surface. RANDALL J. E., 1963. A fatal attack by the shark Carcharhinus galapagensis at St. Thomas, Virgin Islands. Caribb. J. Sei., 3 (4): 201-205. On April 20, 1963 a 10-foot ridge-back carcharhinid shark attacked and killed Lt. John Gibson, USN who was swimming at the surface in Magens Bay, St. Thomas, Virgin Islands without swim mask or flippers. The shark was caught the following day in the bay with the right hand and other remains of the man in its stomach. The shark was examined by the author and ultimately identified as Carcharhinus galapagensis by J. A. F. Garrick who is revising the genus. This is apparently the first authenticated shark attack in the Virgin Islands and the first record of galapagensis from the western Atlantic. RATTRAY MAURICE JR., 1964. Time-dependent motion in an ocean; a unified two-layer, beta-plane approximation. In: Studies on Oceanography dedicated to Professor Hidaka in Commemoration of his Sixtieth Birthday, 19-29. The linearized equations for time-dependent motion in a two-layer ocean with variable Coriolis parameter are transformed into equations identical in form for the surface and internal modes of oscillation. A single equation in meridional transport, valid over the complete range of frequency and wave number, is obtained for each mode of oscillation. This normal-mode equation is compared with the approximate relations used by various authors in previous studies of certain classes of time- dependent motion and shows the range of conditions in which such approximations are valid. Solu- tions to this normal-mode equation together with the Kelvin wave solution include all the linear time-dependent motions in a frictionless, two-layer ocean. In the beta-plane approximation, the free-wave equation is separable into x- and y-dependent parts, thus permitting boundary conditions to be expressed in a simple manner. Representative solutions are obtained for free waves in zonal canals. REYNOLDS R. C., Jr., 1965. The concentration of boron in Precambrian seas. Geochimica cosmochimica Acta, 29 (1): 1-16. Measurements have been made of the boron contents of Precambrian illites from relatively unmeta- morphosed carbonate rocks. The samples range in age from upper Proterozoic to Archaean. The boron contents are similar to those reported elsewhere for normal-marine illites from post-Precam- brian rocks. These data suggest that the boron concentration in sea water has been fairly constant for the past two to three billion years. The results support the view that the oceans have grown throughout geologic time by the accumulation of degassing products of the Earth's crust. The boron method for determining paleosalinities is reviewed, and its limitations are considered. The method is concluded to be valid subject to the following conditions : (I) individual paleosalinities may not be significant within a range of approximately 23 per cent because of uncertainties in the nominal K20 content for pure illite; (2) all samples studied should consist of clay fractions in which the illite is predominantly of the 1 Md polymorph; and (3) the accurate determination of the amount of illite present, based on ~K20, requires that the data be corrected for the presence of K-feldspar. RILEY J. P. and M. TONGUDAI, 1964. The lithium content of sea water. Deep-Sea Research 11 (4) : 563-568. Lithium has been separated from the other ions present in sea water by ion exchange, and determined by flame spectrophotometry--the method shows a variance of 1.I ~. Thirty samples of sea water from all the oceans and major seas have been analysed, and it was found that their lithium contents were proportional to the chlorinity. The average lithium content of water of chlorinity 19"374~o was 183/J.g/l. RODEN GUNNAR I., 1964. Spectral analysis of Japanese sea level records. In: Studies on Oceano- graphy dedicated to Professor Hidaka in Commemoration of his Sixtieth Birthday. 166-180. Spectra of monthly sea levels are investigated for the frequency range between zero and six cycles per year. It is found that the root mean square amplitude of the annual sea level oscillation increases from about 5 cm in southern Sakhalin, to about 14 cm in southwestern Japan. The corresponding

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