The underlying Borrowdale Volcanic Group rocks of the valley were created by glacial activity over 11,000 years ago during the last ice-age.
The soils of the valley are mainly river-washed gravels.
The lake, Rydal Water is 1.18km long by 350m wide. The maximum depth is 17m and Rydal Water covers 0.31km. It is 54m above sea level and is supplied & drained by the River Rothay.
There are two islands within Rydal Water, the larger is Heron Island, the smaller of the two is known as Little Isle.
Buckstones Jum is a classic example of a glacial Hanging Valley.
