Figure F3. Hole 1268A lithology and stratigraphy, shown as percentages for each section (middle column) and as individual observations (right column). The lithologies are grouped as dunites (rocks with 90% olivine), harzburgites (includes all ultramafic rocks exclusive of dunites but the bulk are harzburgites in the strict sense), gabbroic rocks (includes gabbronorites, microgabbros, and gabbroic rocks of undeterminable mineralogy), and intrusion breccias (mixtures of highly altered, probably originally gabbroic material and ultramafic host—these are often so altered that evaluating the original compositions and proportions of the two components is not possible). TD = total depth.