THE MINING AND QUARRY INDUSTRY IQII 29 



about 2500 feet above sea level. It is reached by a rough trail 

 from Kushaqua. 



Two openings have been made in the body which is elsewhere 

 concealed by surface materials. The lower of these exposes the 

 pegmatite over a width of 50 feet and a depth of 25 feet. The 

 upper opening is a little smaller. There are said to be other pros- 

 pects on the mountain which were not visited but which indicate 

 that the pegmatite has the form of a dike and continues for over 

 half a mile along the strike. 



The feldspar is red microcline, showing little tendency to assume 

 regular outlines. The rough and somewdiat broken masses measure 

 a little over a foot in diameter as a maximum. It is rarely free 

 from admixture with other minerals and consequently could not 

 be quarried to advantage for pottery use. Hornblende, tourmalin 

 and biotite are the chief iron-bearing silicates. 



De Kalb, St Lawrence county. The existence of a ledge of 

 coarse pegmatite in this section was made known to the writer by 

 J. H. McLear of Gouverneur. The locality is between East De 

 Kalb and Bigelow, about 3 miles north of the latter place. The 

 pegmatite is exposed in a natural outcrop that has not as yet been 

 developed. 



The principal showing consists of a ledge which exposes the 

 pegmatite for a distance of 75 feet along the strike and 40 feet 

 across it and then disappears below the surface deposits. The 

 outcrop is fresh and free from iron stain. The pegmatite consists 

 of white feldspar and milky quartz in fairly pure aggregates in a 

 matrix formed by a fine intergrowth of the same minerals. The 

 individual feldspar crystals range from 6 inches to 3 feet in maxi- 

 mum diameter. There appears to be very little admixture with 

 other minerals usual to pegmatites. Pyrite, however, may be ob- 

 served occasionally in the quartz. A second ledge in the same line 

 of outcrop is exposed about 300 feet distant from the first, with 

 similar characters. The quality of the feldspar so far as it may 

 be estimated under the conditions, appears to be fairly good. The 

 samples that were examined show it to be practically all microcline. 

 A quantity of first-grade material could be extracted, but the main 

 part owing to admixture with quartz would have to pass probably 

 as lower grade. There is need for thorough prospecting to con- 

 firm the estimate that is formed on the surface showing, as well 

 as to determine the size of the body. 



