International Chronostratigraphic Chart

evidence

Supports the stage and period boundary ages used throughout this pack, including the Cambrian base at 538.8 ± 0.2 Ma on recent editions against 541.0 ± 1.0 Ma on earlier ones. V55 verification basis: this session had no network access to any source — WebFetch was egress-blocked and the WebSearch budget was exhausted — so the cited work was not retrieved and its pagination was not re-checked. No chart edition was opened, so the boundary figures are quoted from standing knowledge of the chart rather than read from it, and the edition in which the Cambrian base changed is not identified.

A evidence is not a place. Drawing it on a map would assert something about the world that no stored fact supports.