1 84 W. J. MILLER PREGLACIAL COURSE OF UPPER HUDSON RIVER 



first passage of the river over the Stony Creek divide probably occurred 

 before the last advance and retreat of the ice-sheet. 



The Saoandaga Eiver 



The Sacandaga Eiver, like the Hudson, shows a remarkable tendency 

 to turn back on its course. On emerging from the Adirondack highlands 

 this stream enters a broad Paleozoic rock valley at Northville and con- 

 tinues its course to Northampton, where it makes a sharp turn north- 

 eastward to cross a broad tongue of hard pre-Cambrian rock, flowing past 

 Conklingville and into the Hudson at Luzerne. As shown on the accom- 

 panying map, certain tributaries of the Sacandaga, like Kennyetto and 

 Hans creeks, also show striking tendencies to flow back on their courses 

 before entering the main stream. The drainage problem involved will be 

 touched on briefly because of its relation to the Hudson Eiver history. 



It is certain that the pre-Glacial Sacandaga flowed southward past 

 Gloversville through the broad Paleozoic rock valley and into the Mohawk 

 Eiver. This must have been the normal drainage as a result of stream 

 adjustment during pre-Grlacial time, since such a course was in perfect 

 harmony with the topography and rock structures. Kennyetto and Hans 

 creeks were tributary to this south-flowing Sacandaga. At or near Conk- 

 lingville there was a pre-Glacial divide, as shown especially by the per- 

 fectly aggraded condition of the channel westward and southwestward 

 from Conklingville and by the distinct flaring of the valley westward 

 from Conklingville. An important tributary (which we may call Batch- 

 ellerville Creek) of the pre-Glacial Sacandaga had its source on the Conk- 

 lingville divide and flowed westward and then southwestward through a 

 great fault trough past the village of Batchellerville and into the Sacan- 

 daga near Northampton, thus offering a fine example of reversal of drain- 

 age for some 15 or 16 miles between Northampton and Conklingville. 



The cause of the deflection of the Sacandaga across the Conklingville 

 divide seems quite clear. Professor Brigham,^ who has made a careful 

 study of the Pleistocene geology of the Broadalbin quadrangle, has shown 

 that a prominent interlobate moraine extends across the southern end of 

 the great Paleozoic embayment past Broadalbin and Gloversville. This 

 moraine has blocked the southward course of the river, which has thus 

 been forced to seek the lower outlet across the divide at Conklingville. 



The Luzerne Eiver 



Thus far we have shown that the pre-Glacial Hudson did not flow 

 southward across the Luzerne sheet, and also that the pre-Glacial Sacan- 



» New York State Museum Bulletin No. 121, pp. 21-31. 



