Why is it difficult for scientists to find fossils from the precambrian period?

The Cambrian period, which began roughly 541 million years ago, represented the start of the Phanerozoic Eon (we are still in this eon today!). Despite the fact that this period of times makes up nearly 7/8 of the Sarah's history, little is known about the beginning of this period due to the fact that Precambrian rocks are metamorphosed (destroying their origin) or heavily eroded.

Most still haven't even been discovered.

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