108 NEW YORK STATE MUSEUM 
crystals of this type which are remarkably clear, brilliant and well developed, 
range in size from 5 to 20 millimeters in diameter. All the faces give 
excellent reflections. The middle edges of the rhombohedron p. (1011) are 
beveled by the scalenohedron K:(2131). The combination shown in 
figure 5 is characterized by the presence of the positive scalenohedron 
c: (6178) in the zone [1011.0112]. The prism a (1120) is present as a small 
face in this zone. In the zone of the pyramidal faces [16.8.8.3.8.8.16.3] 
occur the forms m. (4041) and ¥Y: (19.10.29.6) both lying well within the 
zone and agreeing as to measured angles well within the limits of accuracy. 
Second generation 
Type IV [pl. 18, fig. 7]. The crystals of this type which are pris- 
matic in habit are considerably larger than those generally noted from this 
locality, individuals 30 millimeters in length being not uncommon. Inclu- 
sions of marcasite in microscopic crystals are so plentiful as to render the 
calcite, which would otherwise be transparent, quite translucent. These 
inclusions are distributed along planes parallel to the rhombohedron 
p. (1011). The planes of a (1120) and y (8.8.16.3) are both sharp and brill- 
iant as are, to a somewhat less degree, those of b(1010). A new negative 
scalenohedron is present in relatively small development. The measured 
angles of this form conform closely to those calculated for the mdexes 
(3.15.18.2) which give the Naumann symbol—6R%. This scalenohedron to 
which the letter r has been assigned falls close to (3.16.19.2)—=143R14 
described by Melczer' on the calcite from Budapest, and in the former 
paper cited on page 105 was assumed to be the latter form. The negative 
rhombohedron 3. (0112) is here present as a dominant form developed as a 
series of smooth dull planes. 
Type V [pl. 19, fig. 1-4]. The crystals of this type have been amply 
described by Penfield and Ford as above cited. They differ essentially 
from all previously described in size, color and in their strong twinning 
tendency. In many instances single crystals of this type attain a length 
1Melczer, G. Foldtani Kozlong 1896, 26:79. 
