Last week was the winter holidays for Ruadhri, so we took him out for an airing in Precious the campervan to see some stromatolites near St Pourçain sur Sioule in Allier. These comprise an earth cache, so yet again, thanks to our hobby of geocaching, we made an interesting discovery.

The stromatolites take the form of four boulders in a parking area. That was a tiny bit disappointing as we’d optimistically envisaged a cliff-face of them! But when you consider that stromatolites are the oldest fossils on earth then it’s still impressive to encounter one at all.

Stromatolites are accretionary structures formed in shallow water from layers of cyanobacteria, which are single-celled microbes capable of photosynthesising. Living stromatolites still exist today, and in fact there are some to be found in streams in the Auvergne area of France.

As well as seeing the stromatolite boulders, we went geocaching along the banks of the Allier, as far as the church of St Laurent de Châtel-de-Neuvre, which is very imposing as it’s set high on a hill overlooking the flood plain of the river.

Along the way we saw lots of wonderful stromatolite fossils in walls but resisted temptation to do some dismantling! As it was, sharp-eyed Rors spotted a stromatolite in a small stream, and a little later Chris saw one too.

We stopped for a picnic near the church, where there’s also a rather lovely statue and an interesting modern sculpture called ‘Pilgrimage’.

We retraced our steps along the river back to the van, a little footsore after our good long walk but nothing a cup of tea and bun couldn’t cure us of. Another very enjoyable outing.