This is the third in a series about the textures and patterns in rocks belonging to the Carboniferous Period and exposed in the cliffs at Tenby in South Wales. These photographs illustrate that erosion can happen on several size scales on the same rock surface, with tiny erosional pits (measuring in only millimetres and barely visible to the naked eye) superimposed on slightly larger scale pits (measuring in centimetres). [Don’t forget that you can click on a picture to enlarge it and see a description].
The pitted type of erosional surface, as shown in the images above and below, is probably the result of bio-erosion. However, in the red rocks, If I have identified the stratum and understood the textbooks correctly, then the fine erosional pitting is now taking place on top of fracturing and other features that may indicate exposure of the stratum to wave action and weathering an a much earlier geological time period.
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Jessica's Nature Blog 
Its sometimes difficult to recognise what I’ve read about in the real world, but you’ve illustrated different examples brilliantly with your images Jessica. Great series of articles.
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Thank you, Adrian. The articles I am writing are the result of closer and closer inspection of the rocks in particular locations, repeatedly over the last ten years or so. I have only gradually begun to see, identify, and understand the features, and then only tentatively. I am pleased to share what I am learning.
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