ELECTRONIC	w   w   w dot p a l a e o s dot c o m   s l a s h   p a l e o z o i c   s l a s h   o r d o v i c i a n   s l a s h   a r e n i g dot h t m s e p k o s k i	www.palaeos.com/paleozoic/ordovician/arenig.htmsepkoski	1