GLACIAL AND POST-GLACIAL HISTORY 639 



more indistinct and uncertain terraces at Street Road and Crown 

 Point be assumed not to be wave- wrought, then, because the wave- 

 wrought terrace curve and the delta curve would be made to cross 

 in the southern Champlain region, another succession of events must 

 be assumed: After the ice had retired beyond the Saranac River, and 

 after the 500-foot Ausable and the 5 20-540- foot Saranac deltas had 

 been made in the Hudson-Champlain water body, the uplift at the south 

 took place which inaugurated HigherGlacial Lake Champlain, and fur- 

 ther uplift took place which tipped this water body into the northern 

 end of the basin, causing it to rise to the level of the highest terrace 

 in the upper series. The cutting of the outlet then permitted the 

 upper series of terraces to be made. 



On the whole it seems best to accept the reahty of the upper 

 terraces at Street Road and Crown Point, and to interpret these 

 levels as in part Hudson-Champlain levels, and the lower part of this 

 upper terrace series in the vicinity of Street Road and Crown Point 

 and the entire upper series of terraces from the Bouquet River to 

 north of the Saranac, as due to the waters of Higher Glacial Lake 

 Champlain. While this may now seem to be the best interpreta- 

 tion, it certainly is not demonstrated. 



ALTITUDE OF THE HUDSON WATER BODY. 



If the Hudson water body was a lake, its height above sea-level is 

 indicated by three things: (i) elevation of the southern barrier at 

 that time; (2) height above sea-level of Lake Iroquois, which drained 

 into this Hudson water body through the Rome outlet; (3) the amount 

 of change in elevation of the barrier since it emerged from the Hudson 

 water body, and produced Higher Glacial Lake Champlain. 



Elevation above sea-level of the southern barrier. — If the sub- 

 merged extra-morainic Hudson channel was used at this time, as a part 

 of the outlet valley, and if the Narrows channel was cut entirely 

 as an outlet channel, then the land must have been higher than now 

 by 122 feet plus the amount of the slope of the channel to the sea. 

 With the large volume of water flowing through this valley, it may 

 have been cut to a very gentle gradient, and the elevation of the 

 Hudson water body above the sea-level may not have been more 

 than 35-50 feet. It may have been much more. 



