Back to the cars and north to Rozel and a gentle walk along the cliff path until Arthur made a detour down the steeply dipping cliff. Some of us gave up at this point but the rest moved over some more slippery rocks and a steeply sloping face of rhyolite and down into a little cove. Again these exposures had some very nice spherulites, notably some the size of cricket balls with a nice "star " of quartz at the centre, seen in cross section. Warren Hobbs stood some way off, marking another junction. This time, that of a red mudstone / shale overlain by gritty beds of the conglomerate passing upwards into beds with larger pebbles and cobbles. Though not as old as the Jersey shale formation these beds did represent a minor unconformity and were curious in that some lenses were "inter-bedded " with the conglomerate. This was interpreted as being pieces ripped off by strong current flow and re-deposited in the bed load. In the shales these were also loosely defined mud cracks, but no trace of fossil rain prints that have been found here in the past.
Turning to the back cliff of the cove it was clearly formed of the conglomerate with very large boulders, many faces of which are sheared off in the plane surface. Arthur proceeded to explain the phenomenon as arising from their "extension under pressure" Some of us were clearly confused by this apparent contradiction in terms so Arthur sought to enlighten us. Now, I was suffering a distinct feeling of deja-vu, sure that I have heard this before, but it went as follows:
"With your hand flat on the ground, imagine a full grown , female, African Elephant dressed in a pink tutu" (eyes glazing over as minds were seriously conjuring this image) "Now imagine her pirouetting on the area of your little finger nail. This is the sort of pressure on any point, in every direction, at depth. What happens if pressure in one direction is released. Is it conceivable that this release will cause extension in the rock, still under pressure? Could this result in all the boulders in the conglomerate splitting along the same plane when brought nearer the surface?"
It would explain the lack of breccias or slickensides associated with fault planes that might be a more obvious explanation for this alignment. I will leave you to ponder.
George Raggett