Hi I was walking along a secluded unused beach yesterday and came across these Egg shaped rocks, some are broken but at least 3 still intact. About 8 in total, Thank you.
I'm sure they are concretions, but before I say more, please can you tell us the location (town/bay/etc.)
Thank you Mike, it is a small village called Mayland on the Blackwater Estuary in Essex. The walks are rural and far out, people dont really venture onto the little beachy areas, mainly dogs going for a swim. Will be really interested in knowing what they we had fun with the children digging them up
Thanks for the info.
In this case, it doesn't help me much - I cannot find comments about concretions in the area. But at least I know the rock is London Clay, about 50m years old..
But that's what I think they are - concretions.
Concretions and nodules take many forms, I explain about them here - http://www.nhm.ac.uk/natureplus/message/27257#27257
In addition, yours appear to have thin veins running across them, composed of a cream-coloured sediment or mineral, which seems rather brittle. Also, yours show very good concentric banding.
With any sort of concretion, it is worth looking closely at the centre (assuming it is visible), since there could be a fossil, mineral, or other abnormality there which acted as the nucleus for the creation of the concretion itself.
It is a bit technical, but concretions in the London Clay are discussed in this paper
Lastly, I can't be 100% sure your concretions are actually from the London Clay itself; they could be from much more recent deposits.
Thanks Mike that's great :) much appreciated.