Water of Leith: Stockbridge to Dean Bridge
The lower course of the Water of Leith has cut a steep sided valley to expose sandstone and mudstone of the Gullane Formation, which formed around 350 million years ago. The sandstone layers are tougher and outcrop at several places in the river bed and the banks, while the mudstone is only visible beneath the Dean Bridge. A bonus feature of this section is the two igneous dykes. These are where hot magma was forced up through fissures and cut through the existing rocks. One dyke is exposed just to the east of St. George’s Well, a 3m wide dolerite vein that runs across the river. The site is known for its biodiversity value and is easily accessible from the city centre. A 10-minute walk from Princes Street takes you to the start of this tranquil wooded river walk.