interesting stones

I was weeding today, in the process of which I collect any interesting stones.  My corner of North Essex sits at the southern limit of the last glaciation, and once formed the bed of the river Thames, when it was still a tributary of what is now (I think) the Rhine.  You can read all about it in a useful book 'Essex Rock', now out of print but available from Essex libraries (which is how I read it hence I don't have a copy immediately to hand to check that it was the Rhine that the Thames flowed into).  Thus there are a lot of interesting stones.  I use large flints for decoration in some parts of the garden, and rounded pebbles in others.  In a year I probably collect as many round pebbles as I could buy from a garden centre for about £8.99, but that's not the point.  I haven't yet worked out a use for the pointed stones the size of a finger, which look like fossilised teeth and almost certainly aren't any such thing.  I'm sure something will occur to me, so in the meantime they sit in a jar by my desk.  My favourite stones are the ones with holes through them.  I found one of those today.  I plan to string them on a thin but rot-resistant cord and hang them in the front garden, but there's a way to go yet, as today's find brings my total to eight.  That's not enough for a really good string.