<?xml version="1.0" encoding="utf-8"?><mads xmlns="http://www.loc.gov/mads/" xmlns:mods="http://www.loc.gov/mods/v3" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.loc.gov/mads/
mads.xsd"><authority><topic authority="http://AATesaurus.cultura.gencat.cat/aat/getty_en">Cambrian</topic></authority><related type="other"><topic>Precambrian</topic></related><related type="other"><topic>Ordovician</topic></related><related type="broader"><topic>Paleozoic</topic></related><variant type="other"><topic>Cambrian period</topic></variant> <note xml:lang="en"><![CDATA[ The earliest period of the Paelozoic, extending from about 542 to 488 million years ago. It is characterized by rapid diversification of marine life. Cambrian rocks are the first to contain an abundance of fossils. ]]></note></mads>