CALCITES OF NEW YORE 135 
form of a combination illustrated by Luedecke' under type VIII from 
Jacobsgltick vein, Andreasberg, U: (5491), is identical with the dominant 
form of type I from Lyon Mountain. He notes this type as occurring 
sparingly with quartz, which latter mineral has a “‘hacked, corroded appear- 
ance.” The mine waters from this immediate locality carry considerable 
gypsum, epsomite, limonite and hematite in solution and give evidence 
of having been strongly corrosive. These facts are in perfect accord 
with the conditions noted in connection with type I from Lyon Moun- 
tain [p. 82, 83], and it seems highly probable that in the case of the Jacobs- 
gluck vein, Andreasberg and the Lyon Mountain localities, the first stage 
of calcite deposition took place from a highly corrosive solution which 
was taking up silica while depositing crystals of the steep scalenohedral 
habit of calcite. The absence of all secondary quartz in connection with 
this habit in both localities, points to the fact that the primary quartz 
in both cases was still being dissolved, and its subsequent appearance with 
calcite crystals of a later generation, which latter are characterized by an 
unusual series of second order pyramids, seems to connect beyond question, 
the pyramidal habit of calcite with a crystallizing solution saturated or 
nearly saturated with silica. 
Pyramids of the second order occur in combination on the calcite from 
all the localities of group I with the exception of Sterlingbush. With 
regard to this latter occurrence, the conditions of calcite formation appear 
to vary widely from those prevailing in the other localities of the group and 
the enormous crystals which characterize it may be said to represent an 
advanced stage of calcite deposition absent from these latter. The crystal- 
line limestone which furnished the calcite crystals of Rossie, Antwerp and 
Somerville lie in close proximity to the Potsdam sandstone which may 
fairly be supposed to have furnished considerable silica to the crystallizing 
solutions producing the calcite of these occurrences. 
Passing to the occurrence at Saratoga the coincidence of dissolved silica 
with the presence of the pyramidal zone is much more obvious. Not 
1 Luedecke, Otto, Die Minerale des Harzes. Berlin 1896. pl. 20, fig. 1. 
