 From the perspective of the philosophy of science, it is doubtful whether the genuine discovery of mammalian fossils in Precambrian rocks would overthrow the theory of evolution instantly, though if authentic, such a discovery would indicate serious errors in modern understanding about the evolutionary process.Mammals are a class of animals whose emergence in the geologic timescale is dated to much later than any found in Precambrian strata.Geological records indicate that although the first true mammals appeared in the Triassic period, modern mammalian orders appeared in the Palaeocene and Eocene epochs of the Palaeogene period.