Passing Time

Five million years ago, this area (Marloes peninsula) was a shallow sea. It had time to erode the surface to a flat sea bed. The sea is now 50 metres lower than it was then. What was the sea bed is now a relatively flat plain that ends in spectacular 50 metre cliffs, plunging to the current shoreline below

The rocks that that old sea eroded were formed over 400 million years ago, a time when the first vertebrates and first vascular plants appeared, and the first arthropods took to the wing. They were formed by layers of marine sediments of different types, over a period of 40 million years. The youngest of them, the old red sandstone' was formed by particles eroded from mountains that ran from what is now Scandinavia, through Scotland, to the US Catskills

The strata of those old rocks had already been disturbed by volcanic activity, long before they were eroded by that sea. That disturbance is now magnificenly on display on those 50 metre sea cliffs, where the layers are almost perfectly vertical. A walk along the kilometer or so of beach is a 40 million year geology lesson. Breathing every time - at least for the first 37 years - maybe one day I'll get used to it. Every time, I try to take photographs that do it some justice; every time I fail

Instead, here are pebbles on the beach, as the waves have left them. The old red sandstone is pretty obvious. Somewhere there are also volcanic, coralliferous and grey sandstone, with many variations within those four broad categories

Back on the cliff, the flying arthropods visited the vascular plants, using up every moment of the longest day. Nothing lasts for ever

(thank you for the appreciation of yesterday's picture - I'll catch up with blip eventually!)