CALCITES OF NEW YORK 133 
crystals of the first generation, the highest development of the pyramid 
being found on crystals of type I. 
Comparing the occurring forms of the first generation of Union Springs 
calcite with the forms recorded by Cesaro' from Rhisnes, the striking fact 
is brought out that 12 of the 14 forms occurring at Union Springs also occur 
at Rhisnes, one of which, Y): (19.10.29.6), has been observed only at these 
two localities. 
It is apparent, from the position occupied by crystals of type I from 
Union Springs, which is always that of close proximity to the walls of the 
seam, that the pyramidal type here occupies the lowest place in the crystal 
development, representing the oldest generation of calcite. It is equally 
certain that the scalenohedral type is predominant in crystals of the second 
generation which might possibly have been, in a measure, derived from the 
re-solution of the first generation of calcite. Cesaro finds evidence that 
many of the crystals from Rhisnes of the first generation have been formed 
around a parent crystal having y (8.8.16.3) as the dominant form. 
He announces a theory of genesis of these crystals as follows: 
The examination of these crystals has. led us to the conclusion that 
they have been formed encircling a preexisting second order pyramid and 
were deposited by the action of three successive mediums: the first 
producing pyramidal types, the second forming around the first a com- 
bination, the faces of which are truncations of the lateral edges of y, the 
third depositing around the second stage a crystal having for fundamental 
forms scalenohedrons of the zone [1011.1120]. 
This sequence of crystal formation is in accord with that stated above 
- with reference to the Union Springs calcites, the analogy being further 
emphasized by a comparison of figures 1 and 2 of plate 18 and figure 5 of 
plate 19. Cesaro also points out the fact that the pyramid y occurs also 
on the calcite crystals from Andreasberg as first noted by vom Rath in 1867;’ 
he compares the forms of the Rhisnes calcites with those found by Sansont 
at Andreasberg and points out several similarities. 
‘Cesaro, G. Les Formes Cristallines de la Calcite de Rhisnes. Soc. Géol. Belg. Ann. 
LSSOm OES 
Pe OGuGtt, 
