GEOLOGY OF THE LUZERNE QUADRANGLE 57 



inth 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 narrows, but rather, at that locality, 

 there was an important divide. The Hudson and Schroon rivers 

 both make anomalous turns to the southwest and then join to flow 

 through the highland region of hard rocks instead of continuing 

 southeastward or eastward through one of the low passes in the 

 vicinity of Warrensburg and thence into the Lake George basin. 

 In the writer's paper above cited, the preglacial course of the Hud- 

 son from Warrensburg to the Lake George basin is considered to 

 be through the narrow valley ending at Lake George village. In 

 1920 a hurried examination showed that the broader almost equally 

 low valley from Warrensburg to Hillview is heavily drift-filled. In 

 case the drift in the middle of this valley is lOO feet or more in 

 depth, it may be that the preglacial Hudson flowed through this 

 valley. It will require more careful study to settle this matter. 

 In any case the gradient of the preglacial river was not as great as 

 the present topography indicates, because the Lake George basin was 

 almost certainly appreciably deepened by ice erosion, especially by 

 the removal of considerable relatively weak Paleozoic strata. 



The now extinct Luzerne river (see map) 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 passage of the Hudson over the Stony Creek divide 

 was due chiefly to the fact that, during the ice retreat, the glacial 

 lobe filling the Lake George basin forced the river to take a more 

 westerly course where the channel was cut down enough so that 

 the river kept that course even after the melting of the ice. The 

 deflection of the river over the Luzerne mountain, (preglacial) 

 divided was caused by heavy accumulation of glacial debris in the 

 valley at Corinth. 



As already stated, the deep, narrow, gorgelike valleys at Conk- 

 lingville and just north of Stony Creek station certainly did not 

 exist with rivers flowing through them just before the Ice Age. 

 We may be equally sure that they are not strictly of postglacial 

 origin because in each case the rock channel is completely buried 

 under postglacial materials. Borings made by the New York State 

 Water Supply Commission proved the rock channel at Conkling- 

 ville to be buried under more than 200 feet of loose sediment. 

 Borings have not been made in the Hudson gorge, but the rock 

 channel is there probably not so deeply buried. If we consider 



