9 ▁– ▁John ▁B allen y ▁disco vers ▁B allen y ▁Islands ▁() ▁▁ 1 8 3 8 – 1 8 4 2 ▁– ▁United ▁States ▁Ex pl oring ▁Ex ped ition ▁– ▁led ▁by ▁Charles ▁Wil kes ▁to ▁Ant ar ctic ▁Pen ins ula ▁() ▁and ▁eastern ▁Ant arct ica ; ▁disco vers ▁" Term ination ▁Bar rier " ▁(" Sh ack leton ▁Ice ▁Sh elf ") ▁▁ 1 8 3 9 – 1 8 4 3 ▁– ▁James ▁Clark ▁Ross ' s ▁expedition ▁of ▁ 1 8 3 9 ▁to ▁ 1 8 4 3 ▁discovered ▁the ▁Ross ▁Ice ▁Sh elf , ▁Ross ▁Sea , ▁Mount ▁E re bus , ▁Mount ▁T error ▁and ▁Victoria ▁Land ; ▁extended ▁his ▁Far th est ▁South ▁to ▁ 7 8 °   1 0 ′   S ▁on ▁ 2 3 ▁January ▁ 1 8 4 2 ▁▁ 1 8 5 1 – 1 8 5 3 ▁– ▁Mer c ator ▁Cooper ▁land ed ▁on ▁what ▁is ▁now ▁known ▁as ▁O ates ▁Coast ▁in ▁what ▁is ▁probably ▁the ▁first ▁ade qu ately ▁documented ▁landing ▁on ▁the ▁main land ▁of ▁Ant arct ica . ▁▁ 1 8 7 2 – 1 8 7 6 ▁– ▁ ▁under ▁Capt . ▁George ▁S . ▁N ares , ▁becomes ▁the ▁first ▁steam ship ▁to ▁cross ▁the ▁Ant ar ctic ▁Circle ; ▁re opens ▁the ▁study ▁of ▁ocean ography ▁in ▁the ▁region ▁after ▁a ▁ 3 0 - year ▁gap . ▁▁ 1 8 9 2 – 1 8