The FAMOUS (French-American Mid-Ocean Undersea Study) program was designed to conduct an integrated and detailed geological, geophysical. and geochemical study of a portion of plate boundary where new oceanic crust is generated and where some processes leading to the formation of the oceanic lithosphere may appear more clearly (1). The originality of the program was to include the use, for the first time, of precisely navigated, manned research submersibles in the latter phases of the work at sea and thus enable methods of classical field geology to be applied to the study of the deep ocean floor. Collection of data on a scale ranging from centimeters to kilometers was demanded by the narrowness of the surface expression of the plate boundary. [NOT CONTROLLED OCR]