In middle Cambrian, the Burgess Shale fauna (towards 0,520 B.Y.) will be made up of animals with soft body and animals with hard parts.
(the Burgess Shale fauna (towards 0,520 B.Y.; will be made up; L:In middle Cambrian)
the Burgess Shale fauna (towards 0,520 B.Y.
will be made up
L:In middle Cambrian