▁life ▁forms ▁is ▁mole cular ▁foss ils ▁found ▁in ▁ 2 . 7   G a - old ▁sh ales ▁in ▁the ▁Pil bara ▁C rat on . ▁ ▁These ▁foss ils ▁have ▁been ▁interpreted ▁as ▁traces ▁of ▁e uk ary otes ▁and ▁cy an ob acter ia , ▁though ▁some ▁scient ists ▁argue ▁that ▁these ▁bi om ark ers ▁must ▁have ▁entered ▁these ▁rocks ▁later ▁and ▁date ▁the ▁foss ils ▁to ▁ 2 . 1 5 – 1 . 6 8   G a . ▁This ▁later ▁time ▁span ▁agre es ▁with ▁estimates ▁based ▁on ▁mole cular ▁clock s ▁which ▁dates ▁the ▁e uk ary ote ▁last ▁common ▁ancest or ▁at ▁ 1 8 6 6 – 1 6 7 9   Ma . ▁ ▁If ▁the ▁Pil bara ▁foss ils ▁are ▁traces ▁of ▁early ▁e uk ary otes , ▁they ▁could ▁represent ▁groups ▁that ▁went ▁ext inct ▁before ▁modern ▁groups ▁emer ged . ▁ ▁See ▁also ▁ ▁Columbia ▁( super cont inent ) ▁ ▁Ur ▁( cont inent ) ▁ ▁References ▁ ▁Notes ▁ ▁S ources ▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁ ▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁ ▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁▁ ▁Category : Ar che an ▁Category : Ge ological ▁history ▁of ▁Earth ▁Category : Ge ological ▁processes ▁Category : H istor ical ▁contin ents ▁Category : Imp act ▁ge ology ▁Category : Imp act ▁event ▁min er als ▁Category : Pl ate ▁t ect on ics ▁Category : Form er ▁super cont in ents ▁Category : T ect on ics <0x0A> </s> ▁Pen af iel ▁is ▁a ▁town ▁and ▁a ▁parish ▁in