<?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">grooved rocks</topic></authority><related type="broader"><topic>petroglyphs</topic></related><variant type="other"><topic>grooved rock</topic></variant><variant type="other"><topic>rocks, grooved</topic></variant> <note xml:lang="en"><![CDATA[ Boulders marked with deep, parallel furrows. There is no consensus as to the reason for these grooves, but it is possible that these rocks were used to polish stone tools in prehistoric times, or as timekeeping marks. ]]></note></mads>