Complex sentence: This area was photographed from the air by U.S. Navy Operation Highjump in 1947, and the ridge was mapped on February 20,1959 by Australian National Antarctic Research Expeditions ("Magga Dan"), led by Phillip Law.
Split into simpler sentences: This area was photographed from the air by U.S. Navy Operation Highjump in 1947. The ridge was mapped on February 20,1959 by ANARE (Australian National Antarctic Research Expeditions) (Magga Dan), led by Phillip Law.