Curious rock features on Penyghent

Helen Sergeant
 JOURNAL 
 2009 
 North Craven 
 Heritage Trust 

These photographs show some interesting carved out features on a rock, high up on the ‘nose’ of Penyghent. The rock which the marks are on is just one of several hundred gritstone rocks in the large boulder-tumble down the nose, i.e. the southern end of Penyghent. The question is, were these hollows formed by natural processes or could they be man-made?

Possible natural processes can be roughly divided into two types. In the first, the hollows were formed whilst the gritstone beds were being laid down back in the Carboniferous by, for example, the activities of burrowing creatures. In this case there should be more examples of these hollows in the gritstone beds still in situ on the summit of Penyghent. None have been reported to date. In the second type, the hollows have been formed after the boulder has come to rest in its present position, presumably after the end of the last Ice Age. They are reminiscent of hollows which are formed by pebbles scouring out hollows in the rocky bed of a stream. But if that is the case, where is the stream? And why is there only one rock marked in this way? Similar features in limestone are attributed to the acidic action of water derived from rainfall or decaying vegetation, but the rate of solution of calcium carbonate (limestone) by such carbonic and humic acids is several orders of magnitude faster than the rate of solution of silica (gritstone). To produce such hollows in the gritstone by acidic solution would take millions, rather than thousands, of years.

The hollows are cut through a thin bed in the gritstone which is almost solid with quartz pebbles, so that each hollow is, in effect, ringed by quartz pebbles. Quartz is very hard. If they were made by man, they must have looked quite spectacular when they were first cut, with the quartz showing up as a bright white halo. It is known that quartz was of significance to Bronze Age peoples. Clusters of quartz pebbles and fragments have been found deliberately deposited in ring cairns.The close up photograph of one of the rings shows the halo of quartz pebbles.

Penyghent must always have been regarded as a boundary. It forms the present day and more ancient parish boundary. It was also a boundary between the wapentakes of Ewecross and Staincliffe, and some think that its name suggests it was a boundary much earlier. One of the photographs is taken looking south with the long straight wall going into the distance being the present marker for this boundary.

It will probably never be known for certain just how these hollow features were formed. However, they are unusual enough, with their quartz halos, to merit some speculation about their origin.

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