Gneissfrom the Joshimath Formation at Jyotirmath (Uttarakhand, India).Thisgneiss is from the Protero

Gneissfrom the Joshimath Formation at Jyotirmath (Uttarakhand, India).Thisgneiss is from the Proterozoic Era (2.5 billion to 543 million yearsago).  It is 11.4cm wide at its widest.Manyimportant events occurred during the Proterozoic Era.  Stablecontinents appeared, and began to grow larger by accretion, a processthat took about a billion years.Thefossils of living creatures are abundant from this era – at firstmostly bacteria and archaea, but eukaryotic cells begin to appear asfossils from about 1.8 billion years ago.Thefirst evidence of oxygen build-up in the atmosphere is from thebeginning of the Mesoproterozoic Era (about 1.6 billion years ago). Many bacterial groups died off as a result, but eukaryotic formsbenefitted greatly and their population exploded.  These eukaryoticforms included multicellular algae, and the first animals appearednear the end of the Proterozoic Era. -- source link

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