The gently undulating plains in the Nullawarre area are composed of Tertiary sediments. The soil types consist of Mottled Brown Chromosols on the mounds or very slight rises, with Bleached and Mottled Brown Chromosols occurring in the flats, shallow depressions between the mounds. The shallow saucer shaped depressions, which range from 20-100 m in diameter, may also contain Black Sodosols or Chromosols.