Donkey Rocks EarthCache
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This unique geological feature was formed under the sea millions of years ago, then compressed. The vertical face we now see was in fact the sea bed - it was horizontal at the bottom of the sea.
By the roadside, Bush Green Quarry has a cliff-face 70m across and 10m high that shows 'sole structures' in the almost vertically bedded turbidite sandstones and mudstones (Coniston Grits) of Silurian age, about 400 million years old.
These are knobbly lumps on the surface of the rock, formed by the deposition of hard material on the sea-bed by deep-water currents, and there are more than 1800 of them, mainly types known as flute and load casts, covering six bedding planes.
Further information see Moseley 1978 Geology of the Lake District, p 143, Yorkshire Geological Society.
To claim the cache you need to do some work!
First post a photo of yourself at the site with your GPS then email me two observations -
1. approximately how many 'sole structures' are there per square meter and
2. Within your chosen square meter what is the diameter of the largest feature.
Flow-cast describes structures formed by the movement of graywacke during and after deposition at right angles to the current direction.
Flute-cast describes scour-and-fill structures parallel to the current direction.
Additional Hints
(No hints available.)