SECOND REPORT OF THE DIRECTOR 1905 



2T 



though showing considerable variation in composition and texture. 

 The prevailing type is a reddish, granular rock composed essentially 

 of acid feldspar with more or less quartz, augite, hornblende and 

 magnetite. With the fluctuation in the amount of quartz present, 

 it ranges in mineralogic composition from granite to syenite. The 

 texture is normally gneissoid, with indistinct foliation. It is 

 probable that the gneiss in most districts can be correlated with 

 the Saranac formation of Cushing, but additional investigation is 

 needed to confirm this opinion. 



The ore bodies consist of sheetlike zones or elongated lenticular 

 masses in which magnetite is the predominant mineral, though it 

 is usually intermixed with more or less quartz, feldspar and 

 other constituents of the wall rock. They conform in dip and 

 strike with the foliation of the gneiss and have been little dis- 

 turbed by folding or faulting. 



Among the deposits examined were those at Lyon Mountain 

 from which numerous specimens of ores and associated rocks were 

 obtained for laboratory study. This mine, it may be noted, pro- 

 duces large quantities of magnetite that is almost unique in its 

 purity and is very valuable for the manufacture of high grade 

 steel. The ore bodies are among the largest in the country. They 

 have been opened at various places along the outcrop for a dis- 

 tance of over 3 miles. The workings include about 25 shafts 

 or slopes sunk on the dip of the ore, but only eight or nine are 

 now operated. The ore is a granular mixture of magnetite with 

 feldspar, quartz, hornblende and augite, resembling in its mineral- 

 ogy the surrounding gneiss. The average material as mined 

 carries 50 or 60 per cent of magnetite. The entire output is con- 

 centrated by means of magnetic separators to a product carrying 

 65 per cent iron. The concentrates are in part smelted in the 

 furnace at Standish and the remainder is shipped to various points 

 in New York and Pennsylvania. A new mill is now under course 

 of erection at Lyon Mountain which will give increased facilities 

 for treating the output. 



At Arnold Hill, in southern Clinton county, there are mines 

 that have been exploited since the early part of the last century 

 and are still in successful operation. The deposits extend for 

 over a mile along the strike, taking the form of lenses arranged 

 in successive order. In one locality three parallel "veins" have 

 been opened to a depth of 800 feet. The ore is principally mag- 

 netite, but martite (hematite pseudomorphous after magnetite) 

 is also found in considerable quantities. The ore carries from 



