626 CHARLES EMERSON FEET 



was made. Contemporaneously with at least the lower terraces 

 of this upper series, the Fort Edward outlet valley was eroded. The 

 question as to where the ice-edge was when Higher Glacial Lake 

 Champlain was inaugurated will be . referred to presently, as will 

 also the greater range of the upper series of wave-wrought features 

 from Street Road to north of Crown Point. When the lowest terrace 

 of the upper series was made, the water-level remained constant 

 long enough for a delta to be built on a number of the northern streams. 

 These deltas are capable of another interpretation, however, as will 

 be seen later. 



LAKE ST. LAWRENCE. 



After the upper series of terraces had been completed, the Fort 

 Edward outlet was abandoned, and the water-level fell rapidly to 

 the upper terrace of the lower series. Whether this level was the 

 sea-level or not seems uncertain. The level of the marine fossils 

 falls below it 70-80 feet at the north, and not far from that amount 

 at the south, so far as the writer has been able to discover.^ If this 

 water-level, represented by the upper terrace of the lower series, was 

 not the sea-level, then it represents a lake-level made by the opening 

 up of some outlet, presumably toward the St. Lawrence, which was 

 lower than the Fort Edward outlet. The location of such an outlet 

 is entirely unknown, and its existence is hypothetical. In 1895 Mr. 

 Warren Upham suggested such a lake "occupying an area from 

 Lake Ontario to near Quebec," and "dating from the confluence of 

 Lakes Iroquois and Hudson-Champlain." Concerning it he says: 



From the time of union of Lakes Ii-oquois and Hudson-Champlain a strait at 

 first about 150 feet deep, but later probably diminishing on account of the rise of 

 the land about 50 feet, joined the broad exposure of water in the Ontario basin 

 with the larger expanse in the St. Lawrence and Ottawa valleys and the basin 

 of Lake Champlain. At the subsequent time of ingress of the sea past Quebec 

 the level of Lake St. Lawrence fell probably 50 feet or less to the ocean level. 

 The place of the glacial lake so far west as the Thousand Islands was then taken 

 by the sea. 



As thus defined. Lake St. Lawrence would fall in with the non- 

 fossiliferous part of the lower series of terraces in the Champlain 

 region. It is to be noted, however, that these terraces do not belong 



^ If fossils occur up to 250 feet, south of Vergennes, as reported by early investi- 

 gators, the above does not hold. 



