Question for a rock enthusiast

[Nigel]

“…. it looks like some sort of dodgy grey igneous or metamorphic stuff..... Anyway, the lichen tells me it's Wales, maybe Snowdonia….. I'll venture they're Palaeozoic metarenites / pyroclastics of the Variscan or Caledonian orogens, possibly in the western Cantabrians, the Lake District or Wales.”

Phew. Geology is all about interpretation from a limited set of data. It’s not exactly rocket science, sniffing out a rock from the colour of the lichen on it, but it can still work. Some might use the words ‘luck’ and ‘guesswork’, but that would unreasonably diminish my paycheque.

So let’s just call it ‘effective intuitive analysis’ – with a few extra long words thrown in for good measure.....