There are 3 types of earth: yellow, red, and black. Yellow earth is found in the northern part of Australia around Sydney. Red earth is found in the south, and black earth is found in central Australia. The areas that have black and red earth are the oldest parts of the continent.
Earth types are what form the hills. Hills that have yellow earth are younger, and have a more recent imprint of surface erosion. Hills that have red earth are the most recent, and are large, even though the soil is relatively loose and has been worn away by erosion.
The red and yellow earths have different colors of rock underneath them. The yellow rocks that are found in the yellow earth area are white which make these hills look white. In the red earth area, the rocks underneath are also white, but they are pink in color. This makes these hills look pink.
The black earth areas have no rocks underneath them. This means that all of the material that makes the hills up is the black soil. The hills that have eroded the most are the black earth that make the tallest hills. Because earth is thinner in these areas, they have also eroded the most as well.