BULLETIN OF THE GEOLOGICAL SOCIETY OF AMERICA 



Vol. 30, pp. 415-422 September 3o, 1919 



TOPOGEAPHIC FEATUEES OF THE HUDSON VALLEY AND 



THE QUESTION OF POSTGLACIAL MAEINE WATEES 



IN THE HUDSON-CHAMPLAIN VALLEY ^ 



BY JAMES H. STOLLER 



{Presented hefore the Society December 21 , 1918) 



CONTENTS 

 • Page 



Introduction 415 



The change of course of the Iroquois-Mohawk River 415 



The terraces at Mechanicsville 417 



Deductions 420 



References 421 



Introduction" 



Diiferent conclusions have been reached by geologists as to the question 

 of the southern extension of the postglacial marine waters that filled the 

 Champlain depression. In the present paper th^ writer undertakes the 

 discussion of this problem from a new point of attack. 



The Change of Course of the Iroquois-Mohawk Eiver 



The body of glacial waters which occupied the middle Hudson and 

 lower Mohawk Valley region, known as Lake Albany, received deposits 

 from the Mohawk Eiver during the period when this river was the outlet 

 of the great interior lakes. These deposits formed a great delta heading 

 west of Schenectady and spreading southeastward. With the subsidence 

 of the Lake Albany waters the delta emerged as land surface, forming the 

 great sand plain extending southeastward from Schenectady. The Mo- 

 hawk currents, impeded by the emerged delta deposits, were diverted 

 northward through the preglacial valley depression known as Ballston 

 Channel and discharged into Lake Albany in the Saratoga-Eound Lake 

 region. 



Manuscript received by tlie Secretary of tlie Society January 25, 1919. 



(415) 



