CHEMICAI. STUDY OF DOLOMITES 
43 
AI,03 5.42 
CaCOg 66.41 
MgCOg 20.33 
100.43 
jp. Specimen from Cumberland, England. — The interior con- 
sists of a mass of white crystals, and the surface is composed of 
large red and irregular crystals. We mixed together both kinds 
for the analysis. Specific gravity 2.91. 
SiO, 
PER CENT 
0.68 
FeA 
11.09 
AlA 
2.85 
CaCOg 
57.36 
MgCOg 
28.42 
100.40 
20. A dolomitic limestone from Rochester, New York . — 
slate-colored rock with brown crystals on the surface. The spe- 
cific gravity is 2.79. Both portions of the specimen were ground 
together for the analysis. 
SiO, 
AlgOg and FCgOg 
CaCOg 
MgCOg 
PER CENT 
. 3.05 
. 0.31 
. 43.75 
. 52.96 
100.07 
21 . Specimen from near Gouverneur, New York. — The rock 
is a mixture of gray and white crystals and resembles ordinary 
marble. 
SiOg 
PER CENT 
1.17 
AlA 
2.72 
FeA 
0.17 
CaCOg 
67.24 
MgCOg 
29.88 
100.40 
22 . Specimen from Cape Breton Island. — ^This was kindly sent 
by the Honorable D. Ross MacDonald to whom we express our 
thanks. 
SiO^.. 
FeA- 
AlgOg. 
CaCOg 
MgCO, 
PER CENT 
. 5.19 
. 0.41 
. 2.54 
. 58.12 
. 38.40 
99.75 
