716 SCHUCHERT AND TWENHOFEL ORBOVICIC-SILURIC SECTION 



seems to correlate best with the highest zone of the western New York 

 Clinton^ the Irondeqnoit, an horizon now regarded as the transition zone 

 to the Eochester shales. 



The Anticosti section ceases with the Chicotte . formation and younger 

 Siluric beds are unknown in the northern region of the Gulf of Saint 

 Lawrence. Later beds are known farther south along the north shore of 

 the Bay de Chaleur and at Arisaig, Nova Scotia. 



