The formation used to be more extensive, but has been worn down by erosion over millions of years.

It is as if the emotions form the landscape of the mind like water forms the valleys by long erosion.

There may be sufficient water to produce gullies by erosion.

When strata rise above sea level they get worn down by erosion, such as weather.

Young mountains have high, sharp peaks not yet worn by erosion.

The west bank had been the site of a wooden boardwalk, now washed away by erosion.

They did damage their environment, especially by deforestation and erosion.

Soil loss by erosion on deforested land has been massive.

Over time, these descriptions become problematic as trees die or streams move by erosion.