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 67 499 B MIDDLE MIOCENE LOWER MIOCENE 201.0 210.5 NO AGE GIVEN NO AGE GIVEN NO AGE GIVEN 10.5 22.5 16.5 DSDP INITIAL REPORTS 67 499 B LOWER MIOCENE 210.5 285.5 NO AGE GIVEN NO AGE GIVEN 16 22.5 19.25 DSDP INITIAL REPORTS