During the Carboniferous period, fungi and bacteria had yet to evolve the capacity to digest lignin, and so large deposits of dead plant tissue accumulated during this period, later becoming the fossil fuels.
Tijekom karbonifernog perioda gljive i bakterije tek su trebale evoluirati sposobnost probavljanja lignina pa su se veliki depoziti uginulih biljnih tkiva akumulirali tijekom ovog perioda, poslije postavši fosilna goriva.