 "process paragraph : : 300 millions years ago plants and trees died. The plant and tree remains sank to the bottom of steamy, swampy areas. Layer upon layer of remains accumulated. Eventually forming a soggy, dense material called peat. The peat was buried over millions of years by sand, clay, and other mineral material. Pressure caused by the wait of the materials squeezed water from the peat. With the heat caused by increased burial peat slowly became coal. ", "event : The plant and tree remains sank to the bottom of steamy, swampy areas.", "entity : plants; trees" 
 not exist 