96 NEW YORK: STATE MUSEUM 
ultimate vein filling. On one specimen calcite crystals of the tabular 
rhombohedral habit were associated with compact druses of natrolite in 
small but determinable crystals. 
Type I. Crystals of this type are rhombohedral in habit and present 
two phases which are frequently present together superposed in parallel 
position. Of these, the first phase consists of the negative rhombohedron 
e. (0332) which, when present alone, is terminated by the pinacoid o (0001) 
as shown in figure 1. The crystals average 5 millimeters in diameter and 
are colorless, milky white or light yellow in color. 
The crystals of the second phase are tabular parallel to the Seasoie O 
which is bounded by the planes of the negative rhombohedron ¢. (0221). 
These average 20 millimeters in diameter, measured on the basal plane, by 
2 millimeters in vertical thickness. The combination of a crystal of the 
second phase surmounted by one or more crystals of the first phase in par- 
allel position is quite common and is shown in figure 2. In the composite 
crystals the rhombohedron ¢. is never terminated, the transparent, colorless 
individual protruding from the basal plane of the milky white crystal of 
the second phase. On one large specimen, crystals averaging 15 milli- 
meters in diameter were noted which exhibit the habit shown in figure 3. 
These are thickly incrusted on the basal plane with small individuals of the 
first phase. They are translucent and lhght yellow in color. 
Type II. Crystals of type II which are semitransparent and average 
5 millimeters in diameter apparently represent a later genetic stage. They 
are rhombohedral in habit the dominant form being the negative rhombo- 
hedron x. (0111). The planes of this rhombohedron are much roughened 
by vicinal prominences. The prism b(1010) is present as a well developed 
series of bright planes and the prism a (1120) as a series of bright planes of 
small development. The negative rhombohedron ¢. (0221) of type I is 
occasionally present. 
The positive scalenohedrons N:(5382) in the zone [1011.1120] and the 
negative scalenohedron 0: (2.8.10.3) in the zone [0221.1120] are present as 
well developed forms giving fair reflections. Figure 4 shows a combination 
of this type. 
