1 62 NEW YORK STATE MUSEUM 



made from it was highly commended by Professor Emmons. It 

 was used without concentration. The so called "iron dam" is a 

 dike of ore which cuts across the river back of the Tahawus Club 

 in a northeasterly direction. It has a width of 10 feet or a little 

 more, but includes a good deal of feldspar. 



Along Calamity brook, beginning a short distance from the 

 outlet, ore is exposed for a distance of 500 or 600 feet and can be 

 traced to the west for several hundred feet. It is mostly a fine 

 grained intimate mixture of iron minerals and feldspar, pyroxene 

 and garnet. In the leaner phases it is a ferriferous gabbro. It 

 would appear that this ore occurrence, as well as others of this type, 

 represents an intrusion of a highly ferriferous gabbro in the anortho- 

 site. This ore contains considerable pyrite and is consequently 

 quite sulfurous. The magnetite is in part concentrated in small 

 stringers or veinlets which intersect the gabbro in all directions. 



Between the latter locality and Lake Henderson there has been 

 uncovered by the exploratory operations conducted during the 

 last two years an important ore-bearing area that seems to have 

 been overlooked in the earlier investigations. No mention of the 

 occurrence is made by Emmons or Kemp. The tract is heavily 

 wooded and covered with a stratum of soil and glacial boulders. 

 By excavating a line of trenches, ore has been shown to exist in 

 practically a continuous body, the bounds of which have not yet 

 been determined. The ore ranges from an almost solid mixture of 

 magnetite and ilmenite to leaner material in which labradorite 

 predominates. The deposit has been tested in several places with 

 the diamond drill, of which one of the records is here given. 



£& Feet Inches 



Lean ore, consisting of disseminated magnetite with 



feldspar and pyroxene 19 3 



Rich ore 30 6 



Rock and lean ore, alternating 15 .... 



Rich ore 33 6 



Rock carrying some ore 11 1 



Lean ore 12 .... 



Rock and lean ore 8 .... 



Rich ore alternating with seams of rock 10 7 



Rock 5 .... 



144 11 



Character of the ores. The difference in character of the Lake 

 Sanford ores depending upon their geological associations has 



