129-18 



130-10 



129-25 





129-27 





130-12 





neasured. 



Z calculated 



96-m 



96-30 



96-44" 





J. i '. Kemp — Minerals near Port Henry, N. T. 63 



itself. (See Kaumann-Zirkel, Mineralogie, fig. 13, under cal- 

 cite). This is caused by an oscillation between R and two or 

 more scalenohedra, whose long polar edges, and combination 

 edges are on the diagonals of the R face. Although in general 

 the faces are not well adapted to measurement, enough good 

 results were obtained to indicate 2/7 R 9/5 as one of the scaleno- 

 hedra present above R, and various results for the angle Y led 

 to the suspicion of two others. Below the R face there are also 

 two or more scalenohedra indicated, but the only one of which 

 measurements were obtained proved to be near 13/11 R 9/7. 



T measured. T calculated. X measured. X calculated. 

 3/7 R 9/5 166-21 166-10 



166-01 

 165-50 



13/11 R 9/7 17C43 170-30 Z 



170-25 



170-26 



R4 is also present upon all the crystals. The forms deter- 

 mined by Hessenberg on the combination above cited from 

 Naumann were R2 and 2/5 R2. The crystals are excellent 

 illustrations of oscillatory forms. Still west of this quarry is 

 the Tread way quarry in ophicalcite. Through this rock run 

 at times narrow streaks with pyrrhotite, quite large leaves of 

 phlogopite, brown tourmaline and well- crystallized light- brown 

 tremolite ( ooP, ccPxT, coPco and — P). A visit to the now 

 abandoned feldspar quarry six miles northwest of Port Henry 

 from which came the peculiar tourmaline crystals described 

 by Professor E. H. Williams (this Jour. Ill, xi, 273), revealed 

 the fact that it is probably a great feldspathic mass, either in 

 gneiss or granite (probably akin to the pegmatitic segregations 

 common in many granitic masses), and cut by three narrow 

 trap dikes, now much altered but doubtless originally diabase. 

 The tourmalines favor certain lines, and along these they occur in 

 isolated single crystals and as matted aggregates. Great masses 

 of biotite, as large as a barrel occur also in streaks, yielding- 

 good cleavage masses under the sledge, and fine specimens of 

 rose quartz are less abundant. The quarry is called Roe's spar- 

 bed. 



At Mineville, one of the newer openings (the so-called 

 Lovers' Pit) on Barton Hill is affording crystals and cleavage 

 masses of magnetite of unusual size and excellence. The crys- 

 tals are combinations of O and ocO, and vary up to an inch 

 and more in diameter. They are buried in granular magnetite 

 of great purity. The faces are marked by strise parallel with 

 the O edges and at times running quite around the crystal. It 



