ANCIENT WATER LEVELS OF CHAMPLAIN -HUDSON VALLEYS 255 



the north after the w^aters abandoned the A-B level and 

 before G-D was formed, causing the waters on the north 

 of Port Kent to submerge the old level. 



E-F Lake Vermont at the next lower stage after the opening 

 of the old gorge through which the Hudson now flows 

 at Schuylerville, and when the outlet of the lake was in 

 the Wood creek channel near Dunham basin above Fort 

 Edward, the present divide between the Hudson and 

 Champlain drainage. 



G-H Eepresents the extension of the present inclination of 

 the bed of the Hudson gorge from the divide at E south- 

 ward to the head of tide where the rock floor dis- 

 appears. If the above water levels are correctly 

 measured, it is necessary to suppose that the rock floor 

 of the Hudson is at least as deep at any particular 

 point in the Hudson valley as the line G-H indicates for 

 that point, and since the bed of the rock gorge must 

 have deepened toward the mouth on the south the real 

 depth of the gorge is presumably deeper than is indi- 

 cated by the line G-H. 



H-E-I Indicates the profile of the bed of the rock channel from 

 near Mechanicville to Whitehall at the head of Lake 

 Champlain. 



J-K The approximate level of Lake Champlain, 98 feet above 

 sea level. 



L-M The inclination of the upper marine limit. Note that 

 since E-F was level the land has risen more at the inter- 

 national boundary than at Whitehall for E-F and L-M 

 are not parallel. M is at Mt Eoyal back of Montreal, 

 Canada. 



N-0 A line passing through the highest shell localities from 

 Montreal (550 feet) along the western side of Lake 

 Champlain to near the head of the lake. A straight 

 line passing through the two highest shell localities 

 would meet the surface of Lake Champlain near White- 

 hall. 



P-Q Present sea level . 



R-S The level of Lake George. 



