CHEMICAL STUDY OF DOLOMITES 
41 
A1A-- 
CaCOg. 
MgC 03 
99.35 
0.00 
56.80 
39.39 
II. Specimen from Fassathal, Tyrol. — A dark gray 
mass covered with a layer of dark rhombohedral crystals. 
ture of both portions was taken for the 
gravity is 2.82. 
SA 

AlA 
CaC 03 
MgC 03 
analysis. The 
PER CENT 
. 00.79 
. 00.23 
. 0.71 
. 60.32 
. 38.78 
central 
A mix- 
specific 
100.83 
12. Specimen from Columbia, Pennsylvania. — This sample is 
a black rock containing rhombohedral and irregular shaped crys- 
tals, soft and with a bright lustre. 
The analysis shows it to be a 
limestone rather than a dolomite. 
The specific gravity is 2.69. 
PER CENT 
SA 
0.80 
FeA 
0.31 
AiA 
0.20 
CaC 03 
95.08 
MgC 03 
3.53 
99.92 
7j. Specimen from Lockport, New York . — The rocks belong 
to the Niagaran formation, and are similar to those found in 
northeastern Iowa. The specimen consisted of pink and white 
rhombohedral crystals of a pearly lustre, over a dark gray com- 
pact interior. The specific gravity is 2.84. 
SA 
PER CENT 
0.01 
FeA 
2.07 
AiA 
2.39 
CaA 
55.78 
MgC 03 
39.35 
100.45 
14. Specimen from Cumberland, England. — ^The crystals are 
both rhombohedral and irregular in form. There is a variety of 
color, including pink, white, black, brown and slate ; also irregular 
masses of hard, compact, reddish crystals. The analysis was made 
