34 TRANSACTIONS OF THE [ocr. 17, 
‘The rift or easiest splitting direction runs parallel to the 
east and west joints; the grain, or next easiest, north and 
south ; while the lift, or horizontal splitting, is hardest of all.” 
On the other hand, in many of the granite quarries, ‘‘ the 
rift of the stone is, as the quarrymen express it, ‘on the lift,’ 
that is, horizontal or parallel to the sheets,” while the grain 
may be vertical, or even oblique, and an additional third split- 
ting direction often exists. The relationship thus drawn between 
the division-surfaces of this stone and its cleavage-planes may 
be further illustrated by the table, page 33, which has been 
compiled from the notes on Building-Stones in Volume X. of 
the Reports on the Tenth Census of the United States. 
Physical Characteristics of the Dolomyte. 
The color of the stone, on its natural fracture, is an agreeable 
blue-gray, with a bright sparkling surface, diversified on the 
‘‘cross-grain ” plane by light gray and white lines and stripes, 
more or less zigzag. These plications bear testimony to the 
degree of condensation to which the material has been subjected 
during the folding of the stratum. 
The first influence of weathering upon afresh surface con- 
sists of a seasoning effect, which somewhat darkens the stone, 
sometimes even to a deeper bluish-gray, and decidedly hardens 
its surface, even within a year. ‘Thus, while easily worked when 
fresh from the quarry, it soon resists the edge of a tool to a 
marked degree——a property probably connected with the deposit, 
of calcium carbonate from the ‘‘quarry-water” or ‘‘sap” of 
the rock. Thin veins of calcite are not uncommon, carrying 
crystals or grains of quartz, phlogopite, rutile, etc. After long 
exposure of a quarter or half century, the blue-gray color of the 
dolomyte becomes mellowed by a brownish tinge. 
The texture of the stone, and, to some extent, its density, 
vary with its stratigraphical position. In broad folds with 
gentle dip, the stone has a more slaty structure and looser 
texture; in the crumpled sharp folds, it assumes an increased 
compactness, hardness, and density. From an average speci- 
men, in coarse powder, the specific gravity 2.853, in distilled 
water at 60° F., was obtained, equivalent to a weight of about 
179 pounds per cubic foot of the dry stone—an exceedingly 
high density. This fine texture and homogeneity are further 
shown by the absence of cavities and ‘‘ sand-holes,” such as com- 
monly mar the weathered surfaces of other marbles of western 
New England and of the white marble of Carrara. Another 
indication is the slight absorption of water, shown by the little 
change of color produced when the stone is wetted by rain, and 
