Colours of the Carboniferous

And by that I mean the Carboniferous era - not the results of my last attempt to cook potatoes in a bonfire.

I collected these seven clays yesterday from the trenches of the geological dig. They were all laid down in the Carboniferous era and as such are relatively unusual. by far the largest carboniferous deposits in Britain are the massive layers of limestone that stretch across the country. The limestones were deposited in shallow oceans, but here, where these thin clays are, the land was above sea level and the deposition was in freshwater lakes or ponds. The range of colours is quite beautiful. It seems that at least a couple of them may be lowish in iron (it's difficult to tell with the carbonaceous one) and I'm hoping that as they were freshwater deposits they are low in lime. Feeling optimistic - now to dry and fire!