[Strategerist]

"the sudden appearance of large animal fossils".

To geologists and paleontologists that work in the Precambrian, "sudden" means "over several million years."

[jwalsh07]

To geologists and paleontologists that work in the Precambrian, "sudden" means "over several million years."

My understanding is that "sudden" to the above mentioned fellows means appearing in the strata with insufficent precursors in the lower strata to explain them.

But what do I know, I'm a blue collar guy.