An article published in the journal “Precambrian Research” describes the comparative study of lenticular microfossils dating back to 3.4 billion years ago. Dorothy Z. Oehler and Maud M. Walsh started working on these microfossils and together with other researchers concluded that the ones found in the Kaapvaal Craton, South Africa, are related to those found in the Pilbara Craton, Australia. Probably they were autotrophic organisms that for some phases of their life cycle lived like plankton.