22 NEW YORK STATE MUSEUM 



what slower uplift of the district. But this shore series Is prac- 

 tically limited to the area of this map. It is not found on the Danne- 

 mora quadrangle (plate 8), and is not recognized farther south. 



The contouring of the Mooers sheet is not correct and no precise 

 elevations are given; and the location of bars and of the inter- 

 polated shore line may need some correction. 



The Mooers quadrangle includes the extensive bare-rock areas, 

 due to the stripping of drift from the Potsdam sandstone by the 

 copious glacial waters (see plate 5). The remarkable development 

 of cobble bars indicated in the northwest and southeast parts of 

 the Mooers sheet was due to the abundance of coarse material 

 swept down by the glacial ice-border rivers to within reach of the 

 standing waters. The cobble tracts are the deltas of the glacial 

 streams. Long stretches of the summit shore have not been closely 

 examined. More detailed description of the features of the map 

 will be given in a later chapter. 



Plate 6. This map, the Malone siheet, shows the westward 

 extension of the shore lines, the map joining plate 5. 



Below the marine plane the deltas are mapped only for the 

 Salmon and Trout rivers, but sand and silt plains occupy most of 

 the northern* part of the area. 



On the Moira quadrangle, lying west of the Malone, the shores 

 merely cross the southeast corner, without significant features for 

 the Iroquois and the marine summit, though a lower beach has 

 strong development between Moira and Lawrenceville and west 

 of the latter village. The quadrangle south of the Moira has not 

 been mapped, but it carries heavy deltas and bars on the St Regis 

 river at Dickinson Center and Nicholville. The next sheet avail- 

 able for our purpose is the Potsdam. 



Plate 7. The Potsdam quadrangile, carrying the deltas of the 

 west branch of the St Regis and the Raquette rivers, has good dis- 

 play of the shore features. 



Interesting features occur on the Canton quadrangle, l>'ing on 

 the west of the Potsdam, but as Professor Chadwick plans to pub- 

 lish the Pleistocene geology of that area, it is not here included. 



Plate 8. This map, the Dannemora quadrangle, joins the 

 Mooers slaeet (plate 5) on the south. As on the Mooers sheet, the 

 highest reach of the ^ea-level waters is marked by the termination 

 of the land and ice-border rivers, with their correlating deltas. 

 West of Peru a few gravel bars lie above the theoretic marine 

 plane, but series of heavy bars are beneath the summit level, which 

 is the prevailing relation on all the shores of the marine inlet. 



