cs -Neluded all the ¥ 8 twice daily, e-week periods (LCM) and on lagoon and = bucket hauls “Study periods, observations Ons at various L observations 8 ll values are pendix III, — hoped none1 Supplement- or listed in ts several Chain. eines nly In addition to these two main chains there are several isolated outlying atolls. Altogether the group contains twenty-nine atolls, five islands having no interior lagoon and two, known, submerged banks shallower than ten fathoms. The highest land elevation within the group is about twenty-eight feet. Eniwetok is an isolated atoll lying west of the Ralik Chain and is located some 2,500 statute miles west-southwest of Honolulu, Hawaii and some 4,700 miles from San Francisco. The atoll is some 190 statute miles due west of Bikini Atoll, which together with Ujelang, located some 130 miles southwestward from Eniwetok, are the closest exposed land areas. It appears that Eniwetok Atoll wag originally a volcanic cone, since basalt was found there in 1950 as a result of several deep drilling explorations. The cone probably initially emerged some feet above the water and later was eroded away and absorbed by wave and water action. When the critical depth of sea water required for coral existence and growth was reached by the emerging cone, coral growth probably began. Today Eniwetok Atoll consists of a chain of about thirty small, low islets surrounding an oval lagoon 25 miles long by about 20 miles wide (Figure 1}. The total dry-land area of these islets 1s only 2.5 square statute miles compared with a total lagoon area of 360 square statute miles. The total reef area exposed at low tide is about 32 square statute miles. Most of the islets are less than 13 feet high but are, in some instances, reaching up to 8O to 100 feet above low tide level. the reef. covered by coconut palms Three entrances penetrate Deep Entrance at the southeast side is only about 3/4 of a mile wide ' lying north but it has a depth of 31 fathoms between ELMER and Japtan Islets (Figure 1). ed at South Channel, and is usually nds known as Wide Passage. are on the other hand, is very wide, about six miles, Charted depths in Wide Passage are only 6 to 12 fathoms. nwestward, Southwest Passage on the west side ig even shallower, having depths of only about ee 1 fathom. nN Was Wide Passage have been observed. Maximum tidal currents of two knots in Deep Entrance and of 1 knot in The Eniwetok lagoon is nearly elliptical with its long axis trending north- his pupli- westward. The deepest area is in the north central part of the lagoon, which is the area farthest from the main passes through the reef (Figures 1 and 2). If — the numerous superimposed coral mounds were ignored, the bottom contours would -K (Sunset) show a smooth slope from depths of about 24 fathoms near FRED northwestward to the deepest point of the lagoon, about 35 fathoms. Tr enamine am Ie There appears to be no ee nS ot ne “f