In some places in Svalbard, the coal layers are as much as 15 feet [5 m] thick! In the coal layers, fossil remains have been found of both coniferous and deciduous trees.
Svālbarā akmeņogļu slāņa biezums dažviet sasniedz veselus piecus metrus, un akmeņoglēs ir atrasti gan lapu, gan skuju koku atlieku pārakmeņojumi.