The mats floated on an ocean over Kentucky, bumping against one another and dropping their bark to the bottom. Subsequent volcanic activity provided heat and pressure, the final ingredients used in laboratories to produce coal.
Matendo ya volkeno ya baadaye yalitoa joto na shinikizo, kichanganyiko cha mwisho kinachotumika katika maabara kuzalisha mawe ya makaa.Matokeo ni tabaka tele ya makaa ya mawe katika Kentucky na shahada ya Udaktari kwa Austin.