PLEISTOCENE MARINE SUBMERGENCE 27" 



localities were the first to be relieved of the burden of the ice- 

 sheet (164, plates 9-17). Other localities between Rome and 

 Hamilton had proportionate movement. It will be seen that Rome 

 was the point of largest rise in glacial time, and the station of 

 lowest initial altitude. From Rome northward the glacial uplift 

 was small, but the postglacial was large. Toward Canada nearly 

 all the rise has taken place since the sea-level waters entered the 

 St Lawrence valley. 



The low initial height of Rome is in agreement with the facts 

 of the early glacial drainage in central New York ; for the escape 

 long before Iroquois time was eastward through Syracuse to the 

 Mohawk-Hudson: and the Syracuse channels are today, after 

 uplifting and some filling, less than 400 feet above tide. In apply- 

 ing the mathematics of the table to any particular locality it must 

 be understood that the figures apply to the precise point used for 

 Iroquois or marine altitude. Taking Rome as example, the altitude, 

 460 feet, is the crest of beaches southwest of the city. The lowest 

 part of the divide, the channel head or wasteweir of the latest 

 outflow of Iroquois, the Iromohawk river, is about 430 feet. Hence 

 the initial altitude of that point is 30 feet less than no, or 80 feet. 

 If we add 20 feet for depth of water we have a fall of 100 feet 

 for the river flow between Rome and Schenectady, a distance of 

 92 miles by the railroad. 



The initial height of localities can be approximately estimated 

 by comparison with any near-by shore line (latest) of Iroquois, 

 or a summit beach of Gilbert gulf. 



The profile of the closing Iroquois, plate 11, shows that from 

 Lacona to Chateaugay, or in the area north of tlie Rome isobase, 

 there are shore features higher than the lake level. This implies 

 that the land rose out of the water; in other words, the rise of the 

 outlet, eitlier at Rome or Covey, did not keep pace with the land 

 uplift in the Watertown-Malone district. The greatest vertical 

 spacing or splitting of the bars is at Farr's, 3 miles east of AYater- 

 town, where the highest beach is 62 feet above the profile. The 

 table shows that Farr's rose only 69 feet during the whole of Iro- 

 quois time. But Rome rose 180 feet before and 170 feet after the 

 extinction of Iroquois. It does not seem possible that Farr's 

 could rise 62 feet over Rome in only 69 feet of total rise. The 

 better explanation is that the northern uplift took place rapidly 

 just after the outflow was shifted to Covey, as that outlet, and 

 hence the water level, rose only a small amount before the extinc- 

 tion of the lake. Certainly the land uplift in the Watertown tiis- 



