Stratigraphic changes in quantitative paleoecological patterns.

<p>(a) Abundance of specimens per standardize sample unit (207 g); (b) average specimen size (mean maximum specimen width); (c) drilling frequency (fragmentation-corrected proportion of specimens drilled); and (d) average drillhole size (mean minimum drillhole diameter). Solid small dots represent individual samples and larger gray dots are mean horizon values (arithmetic averages of sample values per horizon). Because horizons 3–5 are represented by one sample each, sample values also represent mean horizon values. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0034576#pone-0034576-t002" target="_blank">Table 2</a> for data summary.