CALCITES OF NEW YORK SI 
on the roof, walls and floor of the cavern. One slender stalactite which 
measured 12.8 centimeters in length and .5 centimeters in diameter was 
hollow for about one third of its length and was lined with crystallized 
calcite. This, together with the remarkable size of the calcite crystalliza- 
tion, points to a condition of extremely slow deposition of lime carbonate 
from a solution which must have remained undisturbed during the entire 
process of crystal deposition. 
The secondary twinning parallel to a hypothetic plane (0112) which 
has been noted in connection with the calcite from Crown Point,' is developed 
to a marked degree on the Sterlingbush crystals where it takes the form of 
parallel systems of sharp ridges protruding from the surfaces of the planes 
of both p. and o. [Fig. 5]. On one crystal, the basal plane of which measures 
15.6 centimeters on the bounding edges, one of these projections measures 
4 centimeters in length and .5 centimeters in hight. The significance of 
the presence of two twinning habits developed to such a degree in calcite 
crystals from localities so far removed as Sterlingbush and Crown Point, 
gains added force from the fact that both localities occur in bodies of crystal- 
Jine limestone of the Grenville series. 
Much praise is due Mr C. A. Hartnagel, assistant in geology, for his 
energy and enthusiasm shown in the collection of this valuable accession 
to the museum collections. 
LYON MOUNTAIN, CLINTON CO. 
Plates 9-12 
These calcite crystals were collected from the Chateaugay mines situ- 
ated at Lyon Mountain in Clinton county, about 23 miles west of Platts- 
burg and near the northern boundary of the area of Adirondack gneiss 
which forms the main outlying mass of the Adirondacks. The workings 
consist of a series of inclined shafts which in some instances extend to a 
vertical depth of 800 feet. It was for the most part in the deeper levels of 
the mine that the openings or “ vugs’”’ were encountered which furnished 
the greater mass of the material collected. 
1 See page 97. 
