84 NEW YORK STATE MUSEUM 
dark blue, running in places to almost dark blue which is the color 
most sought for. In the lighter mottled sorts, the grain is coarse 
and somewhat irregular, with the light and darker calcite segregated 
more or less into separate areas. The individual calcite grains 
mostly have a diameter of about 1 or 2 mm. In the dark blue 
marble, however, the grain is much finer, the calcite averaging only 
a fraction of a millimeter in diameter. The variation in color seems 
to be traceable to the presence of graphitic carbon which 1s scattered 
irregularly through the mass in submicroscopic particles. The pres- 
ence of carbon was indicated in the chemical analysis, but no deter- 
mination of it was made, the actual amount being extremely small. 
The marble is susceptible of high polish and has a luster very 
much like that of some gray granites. It is well adapted for monu- 
mental work and the better grades are mainly used for that purpose. 
Its weathering qualities are attested by nearly a century of use as 
monumental and building stone. For building purposes it has found 
considerable sale in the large towns and cities of New York and ad- 
joining states, especially for public structures, churches and fine 
residences. ; 
The rock face which is most favored for buildings has a medium 
gray tone, while the cut or patent hammered surface of trimmings 
shows much lighter. The selling prices vary with the color and 
uniformity, and range up to about $4.70 a cubic foot which 1s the 
price received for the best quality of extra dark monumental stock, 
sand rubbed but not polished. The lighter grades of monumental 
stone bring from $1 to $2 less a cubic foot. The grades of the 
different quarries do not correspond closely, so that the terms dark, 
extra dark, etc., as used by the several companies are not strictly 
equivalent. : 
There seems to be some relation between the color of the marble 
and the stratigraphic features, though such relation may not be 
uniform or consistent throughout the belt. In general, however, 
the lighter and coarser marble is on top or in the northwestern 
section, while the fine-grained dark comes from the structurally 
lower beds on the southeast. This is indicated by the variation in 
the different exposures and by the results of drilling. 
The St Lawrence Marble Quarries. The quarries owned by 
this company are near the northeastern end, two of which are 
close to the mill and are known as the St Lawrence quarries. The 
third quarry, called the extra-dark, is on a different vein to the 
south and east. Only the last was under operation at the time of 
