Keywords: HardgroundPapers.jpg en Scientific papers on hardgrounds by period Serves as a proxy for hardground abundance over time Calcite and aragonite sea intervals are plotted on the time axis Own Wilson44691 2008-09-13 Graph made by Mark A Wilson Department of Geology The College of Wooster http //www3 wooster edu/geology/MWilson html Bioerosion Carbonates Hardground |