MONTGOMERY COUNTY. 249 



CHAPTER X. 



Brief account of the Rocks, <^c. in the order of their superposition, beginning with the lowest, 

 of each of the thirteen counties, and the half of Tompkins county, which compose the Third 

 District ; the order of the counties being as stated in the Letter to Gov. Seward, and in 

 the Table of Contents. 



1. Montgomery County. 



Under this head the county of Fulton is included, for no other reason than to avoid the 

 repetition which the division would create, and as being generally better understood. The 

 whole area of the county lies to the north of the great elevation or Helderberg range, and 

 contains a less number of rocks than the counties to the west through which the great eleva- 

 tion extends. The rocks are, 1, Gneiss of several varieties, granite, etc., being the Primary 

 rocks ; 2, Potsdam sandstone ; 3, The Calciferous group ; 4, The Black river limestone ; 5, 

 Trenton limestone ; 6, Utica slate ; 7, Frankfort slate and its sandstone. Of these, four 

 only, to wit, Nos. 1, 3, 6 and 7, form important masses as to the surface which they cover. 



The Primary rocks cover the northern part of the 'county, their greatest breadth being to 

 the northwest. They bound the Sacandaga valley at the northeast ; turning to the southwest 

 a few miles below the line of Hamilton county ; forming the high ridges known by the name 

 of Mayfield and Kingsborough mountains ; turning west to the north of Kingsborough village, 

 and joining Klip hill, the north prolongation of the Noses. They form Royal hill, and pass 

 into Herkimer by an irregular line inclining to the northwest. The primary forms a part of 

 the great central mass, being one of the portions of its border. Beyond these limits, it 

 appears but in two places : On Zimmerman's creek, below Lasselsville ; and on both sides of 

 the Mohawk, forming the base of the uplift of the Noses at the east end. 



The Calciferous group forms three areas to the north of the river, nowhere extending more 

 than a mile to the south of its border. It forms the whole surface of the east end of the 

 county, excepting some partial overlying masses. It forms the great south portion of the 

 Noses, and the greater part of the space between the ridge to the east of Mother creek, Little 

 Sprite, and East-Canada creeks. 



The Utica slate separates the three areas of the calciferous ; the eastern edges ranging 

 conformably with the lower rocks, and the western unconformably, being the edges upturned 



Geol. 3d Dist. 32 



