68 NEW YORK STATE MUSEUM 



In the southeastern Adirondacks, it is no exaggeration to say that 

 the larger drainage features have been revolutionized as a result of 

 glaciation. The accompanying sketch map (figure 14) gives a fair 

 idea of the changes, but the interested reader should also refer to the 

 topographic maps of the region. At the southeastern border of the 

 Adirondacks, two prominent valleys extend southward for some 

 miles, one from Northville toward Gloversville, and the other from 

 Corinth toward Saratoga Springs. Each valley is underlain with 

 Paleozoic strata and each is bounded on east and west by highlands 

 of hard prepaleozoic rocks. It is certain that these valleys contained 

 normal preglacial rivers which flowed southward out of the moun- 

 tains. Now, however, the Sacandaga river enters the north end of the 

 first-named valley only to make a very sharp turn back on its course 

 to flow across the mountains and into the Hudson river at Luzerne. 

 A preglacial divide was located at Conklingville as shown by the 

 gorge there; the perfectly graded condition of the valley bottom 

 westward from that place; and the increasing width of the valley 

 westward. This remarkable deflection of the river was caused by 

 the building of a broad morainic blockade across the valley through 

 Gloversville and Broadalbin as already explained. For a long time 

 a lake occupied the valley bottom just north of the blockade dam. 



The Hudson river now flows through a gorge fully a thousand feet 

 deep just north of Stony Creek station, and thence to the north end 

 of the prominent Paleozoic rock valley at Corinth where it turns 

 abruptly to the northeast to flow across the Luzerne mountain ridge. 

 The preglacial Hudson certainly did not flow through the Stony 

 Creek gorge, but rather, where the gorge now is, there was an imporr- 

 ant divide. The Hudson and Schroon rivers both make anomalous 

 turns to the southwest and join to flow through a highland region of 

 hard rocks instead of continuing southeastward through one of the 

 low passages in the vicinity of Warrensburg and into the Lake 

 George basin as shown on the map. The now extinct Luzerne river 

 started on the Stony Creek divide, flowed southward past Corinth 

 and thence through the broad, low Paleozoic rock valley to the west 

 of Saratoga Springs. The cause of the passage of the Hudson over 

 the Stony Creek divide was due chiefly to the fact that during the ice 

 retreat the glacial lobe in the Lake George basin forced the river to 

 take a more westerly course where the channel was cut down deep 

 enough so that the river kept that course even after the melting of 

 the ice. The deflection of the river over the Luzerne mountain 

 divide was caused by heavy glacial accumulation in the valley at 

 Corinth. 



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