[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.

[js1138]

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.

Explain why you wouold expect to find an extensive fossil record of things having no shells or bones.