It’s been icy, snowy, rainy, and all kinds of wet around Sewanee lately, so unsurprisingly, the ground has disgorged a number of unusual items, one of which I came across as I was walking the dogs the other day.

Google was no help– what search terms does one use? “Weird looking stone”? So I wrote my friend Bran Potter, Emeritus Professor of Geology here in Sewanee. His reply below:

    “I think the rock, with those lava-like folds along the surface and the large number of pores, is a piece of slag from the old ironworks in Cowan. If you drive past the Fiesta Grill on that side street and continue towards the limestone quarry, you cross a stream. A walk along the stream  will reveal that the steep slope in the woods is made of many tons of this once – molten waste rock. Sometimes the texture is like coarse glass with holes. Our kids used to scour the field above the woods for artifacts – there were some amazing finds in that area – but sadly they no longer plow the field.       

In the days when the dirt roads of Sewanee often turned into quagmires in the rain, wagon loads of slag were brought up the mountain to spread out on our streets. The slag is reasonably widespread on the Domain but typical pieces are smaller than the one you found. A lot of the slag looks like volcanic cinders.”