CALCITES OF NEW YORK 95 
The crystals are scalenohedral in habit strongly suggesting type I of 
Lyon Mountain. The dominant form is the positive scalenohedron 
V:(6.5.11.1) in the zone [1011.1120], a form which approaches closely to 
U: (5491) of type I Lyon Mountain.1 The shorter polar edges of V:are 
truncated by the planes of the negative rhombohedron II. (0881) present 
as a series of somewhat rounded but readily distinguishable faces. 
The planes of the negative rhombohedron ¢. (0221), which forms the 
termination of this habit, are roughened by vicinal planes in the rhombo- 
hedral zone and gave rather poor reflections of the goniometer signal. Con- 
sistent readings were obtained, however, which taken in conjunction with 
the fact that the faces of this form le in zone with those of the positive 
rhombohedron p. (1011) establishes its identity. The planes of p. (1011) 
although minute are extremely brilliant and furnished excellent points of 
reference. Figures 5 and 6 show crystals of this occurrence. Figure 5 
represents a phase common to the larger and figure 6 to the smaller crystals. 
SUMMARY OF MEASURED AND CALCULATED ANGLES 
. NOZTOX) 
LETTER ANGLE READINGS MEASURED CALCULATED 
° / | ° / 
B, £ ML. 0111 : OS81 8 12h aye. ose 
Ae @ OT11 : 0231 2 107 544 | 107 434 
9: 9. 0221 : 2021 3 101 14 101 9 
Wee We G.Bollll eC. lls. l 4 65 91 | 65 354 
Vee Ge sede dieile Sent 4 
ie) 32 | 53 40 
CHILSON LAKE, ESSEX CO. 
Plate 14, figures 1-4 
The material from which this occurrence was studied was obtained 
in June 1907 from the mine of the Crown Point Graphite Co. which is 
situated 4 mile north of Chilson Lake. The calcite is, in general, asso- 
ciated with pyrite and graphite, the latter minerals lining the walls of the 
seams in parallel bands interspaced with the calcite which formed the 
1 See page 82. 
