84 NEW YORK STATE MUSEUM 
solite and are often free or so loosely attached that doubly terminated 
individuals are readily obtained. They are of a later generation than those 
of type I. In habit they are essentially pyramidal, the simpler development 
showing the predominance of two pyramids in the same series, 7 (8.8.16.3) 
and 4(2243) [plate 9, figure 5]. More complex variations of this habit [pl. 10, 
fig. 1, 2] are found associated with these secondary minerals and, indeed, the 
remaining types to be discussed may be said to represent phases of the same 
conditions of deposition, as they are, at the same time, modified expressions 
of the same crystal habit. The combination shown in plate 9, figure 5 
represents this habit in its simplest development and is found in crystals 
varying from 2 to 5 millimeters in vertical length. The pyramid 7 (8.8.16.3) 
occurs as a series of bright, sharp faces. The faces of the pyramid (2243) 
and of the rhombohedron Y. (0.19.19.13) are of fair brilliancy but frequently 
roughened by natural etchings. The planes of K:(2131) are often present 
on this combination but of relatively small development. On two crystals 
a terminating scalenohedron in the zone [0.19.19.13.19.19.0.13] gave 
measurements roughly corresponding to (7.2.9.11) but on account of the 
imperfect nature of the reflections the form must be regarded as doubtful. 
The combinations shown in plate 10, figures 1 and 2 are variations of 
the above habit, observed on different specimens. Of these the combination 
shown in figure 1 is characterized by the development of small but brilliant 
planes of the negative scalenohedron 8: (4.6.10.1). This scalenohedron was 
first observed on the calcite from Rossie.' The combination illustrated 
in figure 2 differs from figure 1 in the relatively large development of the 
planes in the zone of the negative rhombohedrons. The negative rhombo- 
hedrons s.(0.11.11.7) and¥.(0.11.11.1) are present as deeply etched planes 
giving relatively poor reflections. The combination shown in figure 3 repre- 
sents a modification of this habit in which the planes of the scalenohedron 
K:(2131) partly replace those of 4, and a second negative rhombohedron 
».(0445) terminates the crystal partly replacing the planes of Y. The 
alternate polar edges of 7 are beveled by the scalenohedron U(14.12.26.5) 
1 See pages 62 and 64. 
