NIPISSING GKEAT LAKES. 463 



probably not less than 10 or 15 feet below the Fort Erie beach. This beach is now 13 or 14 

 feet above lake level at Fort Erie. It declines in altitude very gradually westward, but the 

 nodal point where it passes below lake level is not yet known. The lake is now at high stage 

 and Moseley's submerged land, drowned 10 to 12 feet, is almost certainly the low-stage correla- 

 tive of the Nipissmg beach in the upper lakes. If this be true, no recent uplift of the land at 

 Buffalo is required to explain the amount of drowning which Moseley finds around the west end 

 of the lake, but only a change from the low stage during the Nipissmg Great Lakes to the 

 present high stage. The status of the Fort Erie beach in the west end of the lake has not yet 

 been determined. It seems probable that it is somewhat lower than the recent low-stage 

 beach of Lake Erie, though the relation of the earlier beaches to the Algonquin and earlier 

 hinge lines (pp. 442-443) indicates that it is probably not more than 10 to 15 feet lower. 



It was stated above (p. 442) that after Lake Erie had become an independent nonglacial 

 lake it had three stages, the third ending with the end of Lake Algonquin. Later, it had a fourth 

 stage, which resulted from the opening of the outlet at North Bay, Ontario, by the retreat of the 

 ice sheet. Tins took the whole discharge of the upper lakes away from Lake Erie and established 

 its second low stage, which was 10 to 12 feet lower than present lake level and which lasted 

 throughout the time of the Nipissmg Great Lakes. 



CHAMPLAIN SEA. 



The channel of the Algonquin outlet river appears to descend to or possibly below present 

 lake level at Trenton. (See p. 444.) This river ceased to flow when the Kirkfield outlet 

 was abandoned, and the northward splitting of the Algonquin beaches shows that the greater 

 part of the uplift occurred not long after this event, or during the Port Huron-Chicago stage of 

 Lake Algonquin. Thus, if the Algonquin River is rightly interpreted as extending to Trenton, 

 Lake Iroquois, Lake Frontenac, and Gilbert Gulf seem to have disappeared before the beginning 

 of the Nipissing Great Lakes, and the greater part of the elevation of the land at Prescott 

 and Trenton, Ontario, occurred before that time. Indeed, it is not certain but that the 

 Champlain Sea had nearly disappeared and all the uplift, except perhaps about 20 feet, had 

 been accomplished. It seems probable that the marine correlative of the Nipissing beach of 

 the upper Great Lakes is not far above present sea level and might be looked for along the lower 

 tidal St. Lawrence. 



Goldthwait 2 found a heavily developed shore line, which he calls the Micmac beach, extend- 

 ing for 200 miles below Quebec along the south side of the lower St. Lawrence. In 1912 this 

 beach was seen by the writer at many points on the north side between Quebec and Tadousac. 

 It is strong and continuous between Quebec and Ste. Anne de Beaupre. It is 20 feet above 

 the level of the Gulf of St. Lawrence and is horizontal so far as seen. Wave action at this level 

 was evidently powerful and prolonged, for the sea cliff is in places 100 feet high, cut in shale, 

 and the wave-cut bench is everywhere unusually -wide. The Micmac beach resembles nothing 

 in the Great Lakes region so much as the Nipissing beach, but its actual correlative in the lakes 

 region is not yet known. Further studies in the field will be necessary before the later marine 

 shore lines of the St. Lawrence Valley can be safely correlated with beaches in the region of the 

 Great Lakes. 



2 Goldthwait, J. W., The 20-foot terrace and sea cliff of the lower St. Lawrence: Bull. Geol. Soc. America, vol. 22, 1911. pp. 723-724. 



