Sunday stone
"Sunday stone" is an artificial stone composed of
cockfight.[2] Breaks of more than a day would produce an even broader stripe, such as when Christmas fell on a Monday.[2]
The Sunday stone would over time block the drainage pipes necessitating their replacement.[1] Where mines have improved ventilation, reducing the level of coal dust in the air, Sunday stone has ceased to be formed.[1]
References
- ^ doi:10.1144/SP375.22. Retrieved 17 July 2018.
- ^ a b c d Kennedy, Jim. "Sunday Stone". oum.ox.ac.uk. Oxford University Museum of Natural History. Retrieved 17 July 2018.