FOURTH REPORT OF THE DIRECTOR 1907 I9 



The shores of Lake Champlain about its northern end seem in 

 places to be higher than when the chffs were cut. The evidence 

 from many parts of the shore is not conclusive for or against 

 changes of level, either a rising or a sinking. Such channels as that 

 from Champlain village suggest a rising of the water level. It is 

 probable that the highly tilted Siluric slates in Vermont are being 

 crowded up and that downward movements have been taking place 

 among the faulted rocks of the New York shore along the Inter- 

 national border. 



Western, central and northwestern New York. As a result 

 of Professor Fairchild's investigations the story of the succession 

 of glacial waters in western, central and northern New York is 

 approaching completion. Following several introductory and pre- 

 liminary papers, the glacial waters held in the Lake Erie basin in 

 this State have been described in State Museum bulletin io6. The 

 later waters in central New York down to the Iroquois stage are 

 described in the paper awaiting publication. Lake Iroquois is well 

 known in its general character and history, but there yet remains 

 for description : ( i ) the local glacial lakes held in the valleys of 

 the western and northern Adirondacks during the Iroquois stage ; 

 (2) the extinction of Lake Iroquois; (3) the sea level waters which 

 occupied the Ontario basin subsequent to Lake Iroquois and pre- 

 ceding the present Lake Ontario. The past summer's work has 

 been on these three elements of the history, and is briefly summa- 

 rized in the following description. 



(i) Local glacial lakes. All the well defined valleys sloping west- 

 ward or northward from the Adirondack mass must have held 

 glacial waters while the ice acted as a barrier. The largest and 

 most interesting of these local lakes was the one in the Black river 

 valley, which in all the elements concerned in the functions and 

 relationship of such waters is the most excellent known in the State. 

 The larger part of the summer was used in the study of this lake, 

 and its description will form the subject of a future paper. 



(2) Iroquois extinction. A broad ridge of Potsdam sandstone 

 extending north from the Adirondacks into Canada forms the divide 

 between the Champlain and Ontario basins and is the critical area 

 in this study. A rapid examination of the divide shows that the 

 Iroquois waters were held up to the Rome outlet until the south 

 edge of the ice body had receded as far north as the International 

 boundary, but that here the waters found lower escape across Covey 

 hill, the north end of the ridge. The outflow here cut the great 



