1. Index Fossils and International Stratotypes Biostratigraphy and Global Politics

2. Systems, Series, Stages Devonian System Devonian System –Upper Devonian Series Famennian Famennian Frasnian Frasnian –Middle Devonian Series Givetian Givetian Eifelian Eifelian –Lower Devonian Emsian Emsian Pragian Pragian Lochkovian Lochkovian Silurian System Silurian System –Upper Silurian Series Přídolí Stage Přídolí Stage

3. Units Defined by Index Fossils What is an Index Fossil? What is an Index Fossil? Limited Stratigraphic Range Limited Stratigraphic Range Widespread Geographic Distribution Widespread Geographic Distribution Commonly Pelagic Commonly Pelagic Or, tolerant of a wide variety of environments (found in many facies) Or, tolerant of a wide variety of environments (found in many facies)

4. Index Fossils and the S-D Boundary Graptolites * Graptolites * Conodonts * Conodonts * Chitinozoans * Chitinozoans * Trilobites Trilobites Brachiopods Brachiopods Cephalopods Cephalopods

5. Definition of the S-D Boundary GSSP: Global Stratotype Sequence and Point GSSP: Global Stratotype Sequence and Point Point chosen as first appearance of the graptolite Monograptus uniformis uniformis Point chosen as first appearance of the graptolite Monograptus uniformis uniformis Auxiliary index species – the conodont Icriodus woschmidti woschmidti Auxiliary index species – the conodont Icriodus woschmidti woschmidti Stratotype: Klonk, near Suchomasty, Czech Republic Stratotype: Klonk, near Suchomasty, Czech Republic Auxiliary Stratotype: Budňanská Skála/Karlštejn Auxiliary Stratotype: Budňanská Skála/Karlštejn

6. Definition of the S-D Boundary Stratotype: Klonk, near Suchomasty, Czech Republic Stratotype: Klonk, near Suchomasty, Czech Republic

7. S-D GSSP First appearance of Monograptus uniformis uniformis First appearance of Monograptus uniformis uniformis Bed 20 Bed 20 Klonk, Czechia Klonk, Czechia

8. Preserving the GSSP Dr. Ivo Chlupáč

9. Auxiliary Stratotype: Budňanská Skála/Karlštejn

10. Přídolí Stratotype: Požáry

11. Pragian Stratotype: Velká Chuchle

12. Why does it matter? Precise correlations Precise correlations Precise timing for inter-regional comparisons Precise timing for inter-regional comparisons Time frame for discerning global events Time frame for discerning global events

13. Ranges of Conodonts near the S-D Boundary