Category:Ordovician System

• Ordovician System of Africa (4 P)
• Ordovician System of Asia (2 P)
• Ordovician System of Australia (2 P)
• Ordovician System of Europe (163 P)
• Ordovician System of North America (1 C, 61 P)
• Ordovician System of South America (16 P)

L

• Lower Ordovician Series (7 P)

M

• Middle Ordovician Series (8 P)

P

• Ordovician System by paleolatitude (3 C)

U

• Upper Ordovician Series (15 P)