222 Minpralofi;y and Geology of St. Lawrence Co., N. Y. 



In the sand bank, on the borders of the Oswegatchie, and In the 

 town of Ogdensburg, there have been occasionally dug up pieces of 

 Galena. One of them weighed sixteen pounds ; it was apparently 

 rounded by attrition, and had no mark of having been recently 

 brought from a vein. There is however a tradition in the country, 

 that the Indians knew of a mine of Galena; it is certain they had a 

 plentiful supply. 



Proceeding with Mr. Vanden Heuvel on a tour to Rossie, we rode 

 along the north shore of Black Lake. At Judge Davies' residence 

 we observed the quartz rock to alternate with limestone ; the latter 

 was said to be of excellent quality. A few miles beyond, opposite 

 the narrows of the lake, the quartz formation appears on tiie surface, 

 and barrenness is die invariable result. Sometimes a slight inclination 

 is visible in the strata. The road from the border of the lake to- 

 wards Hammond, passes along the edge of the quartz formation for 

 several miles. It presents a very interesting appearance, forming a 

 mural precipice. This has an elevation of near eighty feet, but frag- 

 ments of the rock falling from time to time, have produced a pile of 

 ruins along its foot, and have thus reduced its apparent height. The 

 formation terminates abruptly, and from the extensive plateau formed 

 by the horizontal strata of the quartz rock, we look over the tops of 

 the forest trees which grow in the valley beneath. 



One mile from Hammond, on the road to Rossie, we descended 

 from the quartz formation and arrived at a swamp, over which a 

 causeway has been made. Passing over this causeway we arrived 

 at primitive rocks. The range to which these belong, passes through 

 the whole county of St. Lawrence from east to west and is about 

 twenty miles wide. It crosses the river St. Lawrence at Chippeway 

 ba}^, and at Alexandria, and appears in Canada near Kingston. The 

 rocks of that vicinity have been described by Lt. Bonnycastle, R. E.* 



The first primitive rocks, which I saw two miles fi'om Hammond, 

 very much resemble those of Malvern in England, which I had an 

 opportunity of examining a few years ago. They are chiefly com- 

 posed of quartz, felspar and hornblende. Near the causeway, fel- 

 spar and quartz occur, variously aggregated, the former predomin- 

 ates ; sometimes flesh red, occasionally dark brown red, and some- 

 times much intermixed and colored by epidote. Seams of diis min- 

 eral occur in the rock, but it is rarely crystallized. Proceeding lo- 



* See Vol. xvii, p. 85 of this Jouiruil. 



