Ancestor of Modern Trees Preserves Record of Ancient Climate Change

This fossil wood, called 'Araucarioxylon' (magnification 200X), is reported as coming from the Olentangy Shale of Ohio. This wood shows the 'temperate' type of growth ring. Down is the inner late wood (with small cells), up is the outer early wood (with large cells). "Unfortunately, the Olentangy Shale brackets a wide slice of Middle and Late Devonian time. This particular fossil was said to be from the earliest Carboniferous, but was collected over 100 years ago when the geology of Ohio was much less understood. ...," Scheckler said. "If correctly attributed to the Late Devonian-Early Carboniferous of Ohio, which is not certain, then it shows that some trees during that time suffered cold winters."