Mineralogy and Geology of St. Lawrence Co., N. Y. 227 



is difficult of access as the road passes for some distance in the bed 

 of the river. This quarry is of particular interest. The sandstone 

 is of the same structure as the rock of Heuvel, which is abundant in 

 the county, but it is tinged of a faint reddish hue by oxide of iron, 

 and that rather unequally. The quartz is colored more than the fel- 

 spar. Hence the composition of the rock is more easily observed. 

 It resembles precisely, the rock of Bromsgrove Lickey in Worces- 

 tershire, England, which has been described by Prof. Buckland in 

 the Geological Transactions. A similar rock is found in the vicinity 

 of Reading, Pennsylvania. 



Many private houses at Potsdam are built of this species of stone, 

 and from the regularity of the layers, and the color, they have a 

 pleasing appearance. 



Seven miles from Potsdam, on the road to Pierrepont, is a rock of 

 Serpentine, of a reddish color. Magnesite and talc. 



Eight miles from Potsdam, on the same road, is a fine locality of 

 minerals. Large masses of primitive rocks are scattered on the ad- 

 joining fields, and we there noticed. Granite, composed of adularia, 

 red felspar, gray quartz and black mica. Granite, composed of 

 white felspar, reddish felspar and tourmaline. Brown quartz. Tour- 

 maline in crystals, three inches in diameter. Augite in trap rock. 

 Felspar in crystals twelve inches in diameter, in granite. Black mica 

 in plates seven inches long. 



The masses of rock in which these occur appear not to have been 

 brought from a great distance ; the angles were not much rounded. 

 From Pierrepont to Russel, we travelled the whole distance over 

 primitive rocks. At Pierrepont, near the summit of the hill, I ob- 

 served brown quartz, fluor spar. One mile north of Russel, four 

 hundred yards from the road, is a locality of steatite, grayish white, 

 brown, much intermixed with quartz. Tremolite, inferior specimens. 

 Indurated talc. On a hill to the south west of the village, is a quarry 

 of white limestone, it contains augite, minute crystals, reddish lami- 

 nated calc spar. 



Opposite the quarry, near a farm house on the road, is a vein of 

 sulphuret of iron, much intermixed with black slate, which has been 

 mistaken by the inhabitants for coal. 



At Allen's mills on the Oswegatchie, there are two hills which 

 would probably yield many varieties of minerals if they were thor- 

 oughly examined. Our stay there was short, )^et we found white 

 augite in very perfect crystals two inches long, and seven eighths in 



