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 85 575 B UPPER MIOCENE 12.0 29.5 NO AGE GIVEN NO AGE GIVEN 5 10.5 7.75 DSDP INITIAL REPORTS 85 575 B MIDDLE MIOCENE 29.5 73.8 NO AGE GIVEN NO AGE GIVEN 10.5 16 13.25 DSDP INITIAL REPORTS 85 575 B MIDDLE MIOCENE LOWER MIOCENE 73.8 119.0 NO AGE GIVEN NO AGE GIVEN NO AGE GIVEN 10.5 22.5 16.5 DSDP INITIAL REPORTS