P.672 - §2 1. The prelife era extends over the initial four hundred and fifty million years, from about the time the planet attained its present size to the time of life establishment. Your students have designated this period as the Archeozoic.
Archeozoic era covers the period from 3.8 - 2.6 billion years ago (and these estimates vary among scholars). According to the UB, this period extends from 1000 to 550 mya and there was no life.
During this period the earth formed its crust, and unicellar organisms appeared. There are almost no fossils dating from this era. The few fossiles from this era show bacteria like organisms in a linear fashion.