544 



KIRTLEY F. MATHER 



tributaries to the position of greatest submergence (Fig. 2) before 

 it began to withdraw toward its present location. 



Fig. 2. — The geography of the Ontario-St. Lawrence Valley at the close of Pleisto- 

 cene time. Champlain Sea is at its maximum extent. Lake Algonquin has been re- 

 placed by the Nipissing Great Lakes, which overflow northward down Mattawa and 

 Ottawa rivers. Trent River is a comparatively small stream heading in the Trent 

 chain of lakes and emptying into Gilbert Gulf above Trenton, Ontario. Paleogeog- 

 raphy of New York state after Fairchild. Boundaries in Ontario and Quebec gener- 

 alized and only approximately correct because of scarcity of exact data. 



EVIDENCE OF A PROGRESSIVE MARINE SUBMERGENCE OF THE 

 ONTARIO BASIN 



Napanee Valley. 1 — Napanee River is one of the many south- 

 westerly flowing streams tributary to Lake Ontario along its 



1 1 am indebted to N. B. Davis, of the Department of Mines, Ottawa, for directing 

 my attention to the surficial deposits in Napanee Valley as well as for valuable sug- 

 gestions made in the field in September, 1916. 



