 The geologic record of the Proterozoic Eon is more complete than that for the preceding Archean Eon.In contrast to the deep-water deposits of the Archean, the Proterozoic features many strata that were laid down in extensive shallow epicontinental seas; furthermore, many of those rocks are less metamorphosed than there are Archean ones, and many are unaltered.Studies of these rocks have shown that the eon continued the massive continental accretion that had begun late in the Archean Eon.