The Tay, Britain's largest river
More water flows down the Tay than any other river in the British Isles. Sourced in the very wet West Coast of Scotland, it accumulates water from a wide section of the Highlands. When Scotland was covered in an ice sheet, the river valley was entirely buried in ice. However, when these glaciers began to thin and retreat, ice became increasingly channeled into the valley.
The ice will have filled the present-day estuary, shedding icebergs, sand and enormous boulders into the rising seas. Many of these rocks are still visible today and contribute to the local economy. For instance clay for a long-running brickworks factory in Errol (just west of Dundee) was deposited by this glacier.