aaeer ceroes eae ren in Table I, that enclose a large deep lagoon and that on the ocean side descend very steeply >clpitation is along the reef front into water that is hundreds of fathoms deep (Figure 3). fers are nor- The lagoon is generally deepest in 1ts north central part, produce below 32 fathoms, and it includes about 2300 coral knolls that rise to within a most of which lies autumn few fathoms of mean sea (lagoon) level as well as a 10-fathom terrace that known as borders the reef "along the east, north, and northwest side of the lagoon." 1creased Emery describes this terrace as follows: *neral easter- "The terrace 1s widest where the reef bends outward away from ' of 140° yw the lagoon and narrowest where the reef is indented toward cutofr the lagoon... .. . In the northwest part of the lagoon, ical storms where the terrace ig widest it contains a depression which in special extends about 8 fathoms below the terrace surface .... no Ir typhoons ré years OK. O. Emery, "Submarine Geology of Bikini Atoll", Bull. GSA, LIX, 9, ig 855-59, 1948. of, Eniwetok ith numeroug From the bathymetric chart that appears in Emery's article, ntinuous return this terrace is 1,000 to 5,000 feet wide. precipi- details for the entire lagoon floor. ‘Vity. The it can be seen that This same chart gives the bathymetric A more generalized chart of the floor appears in Figure 2; while Figure 1 shows sample soundings between ELMER and | in late MACK and between BRUCE and KEITH, along the two lines that were followed in alues ig Sampling lagoon water temperatures. tok are The mean tidal range at Eniwetok Atoll is 2.7 feet; 3.9 feet. the mean dlurnal range, During the two periods of synoptic observation, in August, 1957, and in January-February, 1958, the high and low tides were as shown in Table 2, 'tinent to . bathymetry 3, the wind. Clal east winds, 'S in However, some generalizations are warranted. With northeast to south- the surface currents probably form general patterns similar to those that have been observed at Bikini (Figure 5). 1s con- Ree + The general pattern of current systems within the Eniwetok lagoon shifts continually with tidal variations and with changes in the speed and direction of current So far as surface water temperatures are concerned, + OW aahee nt islets Appendix I, the annual range over the nearby ocean is from a mean of 92° F, in late winter (February-March) to a mean of 83.59 in late summer (August-September) as shown in Figure 6, Vertical rere ere e erage ws Sony : TR SeEA a NRRR ra * 9 Sg) gener seas ae ater FE eT # Te > v Spor es