Blog # 2 Why is fossil record hard to interpret?

Since Darwin the fossil record has been pushed back to between 2.3 and 3.5 billion years before the present.   Most of these Precambrian fossils are microscopic bacteria or microfossils. However, macroscopic fossils are now known from the late proterzoic. The ediacara dating from 575 million years ago contain early multicellular eukaryotes. The fossil record and the form of the basis of the science of biostrastratigraphy or the age of rocks based on the fossils they contain.