leg site hole age mnemonic auxiliary age mnemonic top of section depth(m) bottom of section depth(m) special condition age auxiliary age averaged age age top of section(million years) age bottom of section(million years) average age(million years)t data source 9 78 MIDDLE MIOCENE 0.0 21.9 NO AGE GIVEN NO AGE GIVEN 10.5 16 13.25 DSDP INITIAL REPORTS 9 78 LOWER MIOCENE 21.9 140.1 NO AGE GIVEN NO AGE GIVEN 16 22.5 19.25 DSDP INITIAL REPORTS 9 78 UPPER OLIGOCENE 140.1 319.7 NO AGE GIVEN NO AGE GIVEN 22.5 30 26.25 DSDP INITIAL REPORTS 9 78 LOWER OLIGOCENE 319.7 320.3 NO AGE GIVEN NO AGE GIVEN 30 37.5 33.75 DSDP INITIAL REPORTS