This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
OrdHdgd. Crosssection of an Upper Ordovician hardground from Ohio The lightcolored vertical elements are Trypanites borings filled with dolomite Photograph taken by Mark Wilson Department of Geology The College of Wooster wooster edu html Wilson en Wilson original upload log page en OrdHdgd Wilson bytes no taken by Mark