GEOLOGY OF THE LUZERNE QUADRANGLE 7 



rises very abruptly, to even precipitously, iioo feet above the floor 

 of the valley, while its summit lies nearly 1800 feet above sea level. 

 An excellent view of this striking feature of the landscape may be 

 had from the state road a few miles north of Luzerne. 



The group of peaks, called the Three Sisters, just south of Thur- 

 man station, consists of three rather sharp-pointed domes (or sugar- 

 loaf mountains) reaching altitudes of 1920 to 2080 feet above the 

 sea, and 1400 to 1500 above the Hudson river which flows at their 

 western base. The upper portions, or domes proper, rise 400 to 

 600 feet (see plates 5 and 6). Jeffers mountain, 2 miles west- 

 southwest of Hadley, is a good example of a steep dome rising 800 

 feet above the valley floor. Dozens of other domes, rising hun- 

 dreds of feet above the surrounding country, are scattered through- 

 out many portions of the quadrangle. 



In regard to its drainage the Luzerne quadrangle is of special 

 interest not only because the Hudson river, the largest stream of 

 the southeastern quarter of the Adirondack region, flows from 

 north to south across the midst of the area, but also because its two 

 largest tributaries — the Schroon and the Sacandaga — join the 

 Hudson within the map limits. Soon after coming into the quad- 

 rangle, the Hudson river enters an unusually deep, narrow valle}'-. 

 In fact for several miles, between Thurman and Stony Creek sta- 

 tion, this valley is really a steep-walled canyon reaching a maximum 

 depth of 1200 feet (see plate 3). The origin of this deep, narrow, 

 unusually constricted part of the Hudson valley is explained in the 

 chapter on Glacial and Postglacial geology. 



Schroon river enters the Hudson near Thurman at the western 

 end of the large, wide valley in the vicinity of Warrensburg. At 

 Hadley- Luzerne the Hudson is joined by the Sacandaga river from 

 the west. After flowing with a sluggish current for many miles 

 through a wide flat-bottomed valley, the Sacandaga rather suddenly 

 enters a gorge or small canyon fully 500 feet deep near Conkling- 

 ville, and then continues as a swift stream for several miles to its 

 confluence with the Hudson. Many permanent streams, forming a 

 network over the whole quadrangle, feed the mam rivers. Most 

 of these are swift streams flowing in narrow valleys of the rugged 

 mountain area of the quadrangle. 



Nearly all the drainage of the quadrangle passes directly or in- 

 directly into the Hudson river, the only exception being a few 

 square miles along the eastern northern border which drain into 

 Lake George, and thence north into the St Lawrence. 



