Of special significance for human use are loess, limestone, and the mixed sedimentary covers of the interior lowlands of South America. Drainage can be a problem. Boring landscapes, but great for wheat and cattle. Limestone Limestone is made of calcium-rich parts of sea animals. In USA, it is found in Texas.
Surface water can be hard to find.
Erosion can be a problem. Maya built terraces. Beautiful stone for construction. The biggest lowland is the Amazon Basin . This is connected with the Llanos of the Orinoco River to the north.