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There is no photographic merit in this picture, but to me it tells a fascinating tale and that's why I take a lot of my pictures so i thought I might share the tale
This rock is between 201 and 209 million years old, but records just a moment in time or more accurately a few things leading up to that moment in time
First the ripples were laid down in as sand with the sea lapping close to the coast in a warm sea (Britain was just something like 15º to 20º north of the Equator). We know it was a shallow sea because the ripples are small (you get bigger ones in deeper water and the coast must have been close because of what follows
Then without disturbing them a layer of finer sediment with mud was laid down on top of those ripples and that dried and cracked
Then .. all of a sudden (and it must have been quick so as not to really wet the muddy layer and lose all the cracks) a layer of sand was washed in (OK it may not have been Tuesday, but you get the picture)
Finally of course, and over a much longer timescale, this was all solidified to rock and then the slab fell out of the cliff and the muddy layer was eroded away (because it's weaker) and we get the filled mud cracks standing proud on a welsh beach
All I did was prop it up to get a bit of shadow on the ripples and mud cracks AND I put my lens cap on it to give it a sense of scale (something geologists typically do)
I
Rocks
This rock is between 201 and 209 million years old, but records just a moment in time or more accurately a few things leading up to that moment in time
First the ripples were laid down in as sand with the sea lapping close to the coast in a warm sea (Britain was just something like 15º to 20º north of the Equator). We know it was a shallow sea because the ripples are small (you get bigger ones in deeper water and the coast must have been close because of what follows
Then without disturbing them a layer of finer sediment with mud was laid down on top of those ripples and that dried and cracked
Then .. all of a sudden (and it must have been quick so as not to really wet the muddy layer and lose all the cracks) a layer of sand was washed in (OK it may not have been Tuesday, but you get the picture)
Finally of course, and over a much longer timescale, this was all solidified to rock and then the slab fell out of the cliff and the muddy layer was eroded away (because it's weaker) and we get the filled mud cracks standing proud on a welsh beach
All I did was prop it up to get a bit of shadow on the ripples and mud cracks AND I put my lens cap on it to give it a sense of scale (something geologists typically do)
I
Rocks 
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