Читать книгу Walking in the Yorkshire Dales: North and East. Howgills, Mallerstang, Swaledale, Wensleydale, Coverdale and Nidderdale онлайн

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It is this layering too that is responsible for the impressive waterfalls in Wensleydale, in particular the falls on the River Ure at Aysgarth, and the great cascade of Hardraw Force above Hawes. Shake holes too are a common feature of the bands of limestone, and nowhere are they more spectacular than beside the Buttertubs Pass.

While geology and subterranean force may have laid the foundation for the Dales landscape, it is the natural elements that have been responsible for moulding it. And nothing has been more dramatic in its effect than the action of ice. During the last half-million years of its history, Britain has been subjected to at least three major ice ages, when vast glacial sheets, many hundreds of feet thick, inexorably fanned out from the mountain areas across much of the country. Although the general topography of the area had already been set before the ice ages began, each new advance scoured the land back to the very bedrock, gouging valleys ever deeper, and straightening their erratic fluvial courses. When the thaws came, boulder and clay debris were dumped far from their origins, and unimaginable volumes of water were released. What we see today are just the finishing touches left by the latest glacial period, whose icy tendrils melted from these valleys 12,000 years ago.