>
>
> The earliest accepted trilobites fossils appear in the Atdabanian of
> Siberia. The pre-Atdabanian fossil faunas are in fact referrred to as the
> pre-Trilobite faunas. The anomalocaridids appear in the Chengjiang faunas
> of late Atdabanian age. The gilled lobopod fossil to which I referred was
> from a formation of late Atdabanian to early Botomian age. The diverse
> arthropods of the Burgess shale are much later in the middle Middle
> Cambrian.
A brief comment on part of Keith's excellent post. In my post on the faunal
succession in the Flinders Ranges I mentioned the presence of two faunal
assemblages in the Wilkawillina Limestone, the lower one (FA I) being
pre-trilobite, the later (FA II) containing trilos. FA I is very early
Atdabanian whereas FA II is early to middle Atdabanian. Correlation with the
Siberian platform was (from memory) by Archaeocyaths and trilos.
In Christ
Jonathan