How are mountainous and lowland areas depicted on a geological map?

In order to accurately determine the height of the earth’s surface, as well as the shape of the relief, it was decided to distribute the relief relative to the height using a color scheme.
Thus, the plains differed from the rest in that they were highlighted in pale green.
Alpine ridges and peaks were marked with dark brown, less often red.
The small hills were pale yellow.
The depressions are dark green.

The depth of the ocean was determined in the same way.
The shallow areas were blue, and the deep depressions were dark blue.