As part of the Geology project Mr David Leather MSc, a local geology expert, member of Yorkshire Geological Society and author of guide books on the Yorkshire Dales came to survey the Park in February – recommended by the Wharfedale Naturalists. David is doing a full report on his findings, and making recommendations for how FOPP can capture the information so as to share the ancient story of the Park’s formation.
One of the first remarks of this retired geography teacher from Salts’ Grammar, as he stood looking out over the valley towards Wharfedale, was that the terrain was unusual, and not a typical ‘text book’ glacial landscape.
Looking at his maps, the Park itself sits on and area of interlocking millstone and Guiseley grit layers that make up the Chevin. These were laid down many millions of years ago, when the Park was part of a big river delta. In the nearby quarry at Fairy Dell, there are signs of ‘tidal lamination’ – fine layers of rock laid down by tidal action, that David was particularly interest in. You could, he said, even see evidence of the weather and tides of the time. The underlying acidity of the grit gives some parts of the Park, like Great Brow, the characteristic acid grassland.
Coming forward in time; the valley between the Park and Menston, was formed, as we knew, by a finger of the Wharfedale Glacier. Some areas of the Park are still covered in boulder clay, a silt-like deposit found in and beneath old glaciers – the result of the ice wearing down dislodged rocks in its path. Therefore, as much of this rock was limestone from The Yorkshire Dales, the Park should have areas of limestone (alkaline) loving plants eg wood sorrel, herb robert, wood anemone, cocks foot and Yorkshire fog; which it does. David said that in the surrounding area eg around The Oaks, there were signs of lateral moraine – built up deposits of debris that form on top of a glacier.
So, the Park has gone through some interesting times, a tropical river delta, and a freezing ice-age wasteland . Leaving plants that love both acid and alkaline conditions. We look forward to discovering more of this ancient story, and linking it with the ecology, archeology and cultural history of the Park – not to mention work done at Chevin Forest Park.