This volume covers Leg 16 of the cruises of the Drilling Vessel Glomar Challenger. The main objectives of Leg 16, between the Panama Canal and Hawaii, were: (a) to examine the ages of volcanic basement, the stratigraphic sections, and the depositional histories of the ridges surrounding the Panama Basin; (b) to supplement the series of holes begun on Legs 5, 7, 8, and 9 to examine the depositional and tectonic histories of the eastern equatorial Pacific; (c) to study the metalliferous sediments reported above basalt basement on Legs 5, 7, and 9; and (d) to critically evaluate the physical properties measurements made on board the Glomar Challenger. Glomar Challenger left Cristobal, Panama, on February 2 and arrived in Honolulu, Hawaii, on March 30, 1971. During the fifty-six-day leg, the vessel traveled about 6400 nautical miles and drilled twelve holes at nine sites.