Hmmm - no - it is not a trilobite; various factors about the geometry are not right.
But I am not sure what it is.
It is a bit reminiscent of the brachidium inside a brachiopod, but that's not good enough, either.
Do you have any more photos of this specimen or of other specimens of the same thing?
PS. Trilobites have been collected from the Annick Water area, eg. Phillipsia eichwaldi (http://www.bgs.ac.uk/Palaeosaurus/Record.cfm?sample_id=127878)
-- so it was a good guess. Keep looking.
Hi Mike, Leon is delighted that I am able to give him some information on our finds at last. I will try to take some more pictures tomorrow, it is very small and not easy to work with but I shall do my best. Thank-you for your time and knowledge
That makes all the difference.
Now I have to retract my earlier comment: in fact I think these do represent trilobites; each mark appears to be a mould rather than the animal itself.
There is not enough to tell which genus/species it might be.
Thanks Mike, It is great to know what the fossils are It sounds soppy but it really is amazing to hold something that was alive millions of years ago in the palm of your hand. Would love to find anything that can be used to understand the past better, waiting to hear back from the museum curator regarding all our fossil finds, If they can be of use then we will gladly donate them. I am glad I documented each find spot now!