The Lava Cast Forest lava flow on the NW flank of Newberry formed about 7,000 years ago. It contains hollow tree molds that stand above the surface of the flow. These features formed when flowing lava chilled around standing tree trunks that subsequently burned from the heat of the lava. Horizontal tree molds formed around trees that had either previously fallen or were toppled by the advancing lava flow. 
This heart-shaped tree mold was produced during an eruption along the East Rift Zone that began on 7 October 1968. Molten lava solidified around the tree, which eventually burned away, leaving the mold with incandescence from the hot rock below.
