ANALYSES OF DOLOMITES 
353 
PER CENT 
S 1 O 2 ..................................... 3.96 
Fe 2 0 3 and AI 2 O 3 . 0.62 
CaCOs 55.42 
M'gOOa 40.44 
Total................ ..................100.44 
The specific gravity is 2.84. The specimen is quite a pure 
dolomite. 
12. Specimen from Kasota, Minnesota. The color through- 
out the mass is light yellowish brown. 
PER cent 
S 1 O 2 9.08 
Fe 2 0 3 and AI2O3. 30.91 
CaCOs, ................................... 51.80 
Mg OO 3 38.64 
Total 100.43 
The specific gravity is 2.72. 
13. Specimen from Freiberg, Saxony. A yellowish-grey cry- 
stalline deposit on quartz. By the analysis, it can not be con- 
sidered a dolomite or even a limestone. 
per cent 
Si0 2 ..................................... 26.60 
Fe 2 0 3 and A1 2 0 3 . 51.41 
CaCOs 4.46 
MgCOa 17.54 
Total............ 100.01 
The specific gravity of the crystalline deposit and the quartz 
together, the entire rock, is 3.52. 
The analyses show that dolomite is quite a variable mineral in 
its composition, and many formations called dolomite can hardly 
be called by that name. 
We desire to express our thanks to Lawrence R. McKay and 
William E. Moore for making the analyses of the specimens con- 
sidered in this paper. 
Cornell College;, 
Mount Vernon, Iowa. 
