The valley is cut into gritstone but limestone is very close to the surface at the bottom of the valley. As the river crosses the different hardness bands of gritstone sections of valley have formed as gorges or wide sections. The river is guided by a geological fault line running along the valley floor from New Mills to Marple Bridge and resulting in the very steep west side to the valley and easier sloped east side. The displacement is some 150 meters.
The flora of the valley varies greatly from deciduous woodland to open meadows. The floor of the valley has many areas of marshland with a large variety of water loving plants. The drier sandy areas support a different array of plants including gorse and primrose.
Animal life is varied with the usual rabbits, fox and badger. Somewhat more unusual inhabitants are mink and also small groups of Roe Deer and Muntjac that wander the valley but are rarely seen. At Roman Lakes a large variety of both water fowl and other birds can be seen. Herons fish all day long both in the river and the Lakes. Bats and owls are also common in the area.
From September to December migratory fish, salmon and sea trout, make their way up the River Goyt jumping the weirs as they go, making a spectacular sight if you are lucky enough to spot them. The weir near Roman Lakes is the best place to see them.