and outside communication forces, as the present structures on this island will be largely unusable by the time they are required for the next experiments, (c) new facilities for approximately 200 on each of four islands; namely, Bogallua Island, Engebi Island, Rojoa Island, and Runit Island, which will be used during the preparation period for each test ana will be either expendable or of light construction that can be readily and easily removed from these islands and stored on Parry Island during the roll-up or interim period. The islands that constitute the usable land areas of the Atoll and with which this project is concerned, consist of separate deposits of coral sand supported by a shelf-like reef. These deposits have been built up to eleva- tions varying from 8 to 15 feet above the level of the reef proper and also very considerably in size. The elevation of the reef proper is such that at periods of low tide, it is barely awash. The Island of Eniwetok, the largest of the Atoll, has an area of approximately 355 acres. Bogallua, probably the smallest island considered for possible exploitation by this Report, has an area of approximately 23 acres. SURVEYS: General. Section II of this Report describes the survey work that has been done at the Atoll with comments as to accuracy and adaptability to this project. The following describes proposed permanent horizontal and vertical control and scope of field work to be performed in connection with the design of the facilities. Field work necessary for construction is covered in Sec- tion V. Permanent Horizontal Control. A control network based on the following recommendations would provide adequate primary control for any contemplated operations. (a) Accept the geographical location of station North Base and the IV-2