But the changes were really violent at times during and after the phase of deposition. It is easy to see that whole sections have been worn away or have disappeared through some other mechanism, so that later layers have overlain discontinuities that now show up as junctions in the layering.
There is another local proof that the depositional/erosional processes were repeated over time. Harder rocks and pebbles might remain from an earlier phase to be incorporated in a fresh new accumulation of mud which will in turn be compressed and hardened to some degree. Now, as the softer, younger mudstone is worn away the earlier, harder rock fragments or pebbles within are revealed.
Occasionally there was something in the water that would not decompose so that millions of years later its pattern is once again exposed to the light as a fossil - either of the organism itself or of the indentations that it left behind.
The remains of some other organisms are much more obvious to the casual observer. The most recent accumulation, particularly easily seen at the north end of Seahouses' south beach below the golf course, is a soft consolidation rich in shells.
But in terms of the numbers of organisms pride of place must go to a different type of rock altogether - to the limestone layers. Masses of small corals and more microscopic sea creatures were needed to contribute their calcium-rich skeletons to form each block of limestone. And we've millions of tons of the stuff around here. Indeed, it formed the basis of the lime industry which was the source of the wealth underlying the original development of Seahouses - as you will have read if you have seen the information panels down at the harbour-side.
Anyway, the resulting rock is harder than the mudstones and shales. The layers are more massive, probably best dignified as 'strata'. And whereas the softer rocks erode layer by layer the limestones tend to crack in an almost regular, right-angled pattern leaving blocks looking as if they had been dumped there from some man-made quarry.
(Did you spot the 6" ruler on top of the nearest block?)
Being a slightly harder rock (albeit nothing like as hard and resistant as granite, say) the result of erosion by the sea waves is to leave the limestone layers still visible when the softer rocks have been weathered away. Since nearly all the Seahouses rock layers slope one way or the other, what is left exposed is a sloping edge running out to sea, as here at the aptly named Shoreston Rocks on the shore north from Seahouses towards Bamburgh.
Similar in some respects are the relatively massive Seahouses sandstones. They sparkle in the sun even when they are dry. They are a relatively soft rock, as some folk have found.
Will the rock outlast the relationship, or vice-versa?
The sea can gouge out any rock showing any form of weakness. It can leave a dramatic gully, as here, south-east of the harbour.
Perhaps it is even more dramatic when soft mudstone and coal layers are washed away, leaving harder rocks overhanging as a potential cave - to collapse sooner or later, one stormy day at high-water time, as a tumbled collection of blocks
Quite apart from the kind of rock that has "Seahouses" running right through it, there are lots of rocks under and around the village and beaches of Seahouses. They tell of the area's history going back a good few million years.
There were also some phases when the Seahouses area became a dry sand desert. But perhaps the most interesting phases were when tropical forests were growing and dying, half-flooded so that their remains could not rot away fully. Then their residues accumulated as peaty organic matter which was later compressed and converted into coal. Much of modern Seahouses is sitting on coal seams - fortunately too thin and impure to be worth digging out.
The thin layers are soft enough to lift off with the fingers. The seams extend out to sea in places: the result is that a small proportion of Seahouses sand is of black coal particles, usually washed into local patches. That's a six-inch ruler, by that way - 15 centimetres. It features in a number of these photos to give an idea of scale.
The thin parallel layers that aren't black were originally simply accumulations of mud, now compressed into mudstones or shales. Each layer marks an accumulation period of unknown duration. Nor can we now tell what went to make up each layer. But the changes in colour and hardness from layer to layer prove that circumstances must have changed many and many a time throughout that carboniferous period. One outcome, though, is the production of patterns to inspire any Seahouses artist.
And today's rock movements may well be dwarfed by cataclysmic faulting in past ages. It takes a significant earthquake to slide huge masses of rock up or down or sideways relative to one another. But that's evidently what happened here, for example.
But all these rocks are left-overs from millions of years ago. What's been happening since? Well, whatever might have been sitting on top of today's Seahouses rocks was scraped off by a succession of glaciers during the ice ages and dumped somewhere else, probably on what is now the bottom of the North Sea. But when all such movements were coming towards their end, a mere ten thousand years or so ago, the glaciers which had been scraping bits off central and southern Scotland dumped their load on top of us ! It was a total mixture of everything from boulders to the finest clay, so it's sometimes known as boulder clay. Another name is glacial till. And here is some of it, on the exposed edge of the Seahouses golf course
