122 NEW YORK STATE MUSEUM 
well developed planes of fair brilliancy. The faces of the prism a are 
striated parallel to the middle edges of D. The combination shown in 
figure 2 which occurred on only one specimen differs from the preceding 
one in the indexes of the negative scalenohedron which in this case are 
(3.16.19.2) =». This scalenohedron was first noted by Melczer'! on the 
calcite from Budapest. The prism a which in the preceding combination 
is deeply striated is represented in this combination by smooth planes of 
maximum brilliancy. The combination shown in figure 3 which was noted 
on one specimen differs from the two former in the absence of the scaleno- 
hedron D as well as the negative scalenohedrons previously noted. The 
positive rhombohedron p. (1011) and the scalenohedron K: (21381) are 
present in relatively small development. The planes of the prism a are 
striated parallel to the zone [1011.1120]. 
Type IV [pl. 26, fig. 4, 5]. Crystals referable to this type are quite 
common, being noted in as many as eight specimens. They are of rhombo- 
hedral habit, the preponderance of the rhombohedron c. (0.13.13.1) giving 
to them an aspect almost prismatic. The rhombohedron 4. (0445), which 
with 8. (0112) terminates the type is of variable development from a face 
equal to 8. (0112) in habit to a mere line, as in figure 4. Vicinal planes are 
frequent in crystals of this type and are often present to such an extent as 
to modify the basal edges to curved lines and give to the crystal the aspect 
shown in figure 5. Twinning parallel to the basal plane o was noted. 
Type V [pl. 26, fig. 6,7]. A combination of rhombohedral habit refer- 
able to this type is shown in figure 6, the dominant forms being the nega- 
tive rhombohedrons 3. (0112) and a new negative rhombohedron (0771) 
to which the letter Q. has been assigned. The negative rhombohedron 
9. (0221) is present in small development as well as the prism a (1120) and 
the negative scalenohedron Y (12.32.44.13). The latter form was noted by 
vom Rath? on the calcite from Bergen Hill, N. J. A more complex combi- 
nation of this type, shown in figure 7, is of rhombohedral-scalenohedral 
1Melczer, G. Fdéldtani Kézlony 1896, 26:79. 
vom Rath,G. Zeitschr.f. Kryst. 1877. 1:604. 
