White Rock River

The White Rock River is a river in the South Canterbury area of New Zealand. It rises south of the 1,525 metres (5,003 ft) Mount Nimrod / Kaumira in the Hunter Hills and flows northeast then north to join the Pareora River.
The white rocks are a cliff face with many layers of rock which are millions of years old, often used for study by scientists and school students.

Source: Wikipedia https://en.wikipedia.org/wiki/White_Rock_River