188 
CEMENT MATERIALS AND INDUSTRY. [bull. 243J 
Analyses of Greenbrier limestone from Maryland." 
Silica (SiO a ) 
Alumina (A1 2 3 ) 
Iron oxide (Fe 2 3 ) 
Lime carbonate (CaC0 3 ).. 
Magnesium carbonate 
(MgC0 8 ) 
13. 65 
5. 44 
79.16 
1.21 
13. 46 
12.48 
72.92 
1.15 
8. 57 
2.38 
58. 73 
.86 
20.9517.00 
41.10 2.74 
37.35 64.12 
. 91 15. 75 
4.4: 
3. 65 
2. 70! 8.44 
56. 73 85. 87 
6.38' 1.30 
8 
9 
11.52 
5.11 
3. 37 
2. 56, 
74.48 
89.08 
10.99 
3.17 
10 
5. 24 
1.98 
84. 58 
7.49 
1. Gerringer and Inglebart's quarry, Garrett County. 
2. OfTutt's quarry, Garrett County." 
3. Crabtree, Garrett County. 
4. South of Negro Mountain, Garrett County. 
5. OfTutt's quarry, Sarrett County. 
6. Findley's quarry, Piney Run, Garrett County. 
7-9. Mouth of Stony Run, Allegany County. 
10. Barrelville, Allegany County. * 
ADJACENT SHALES. 
The following anatyses^ of Carboniferous shales from near Corinth, 
Garrett County, will serv r e to illustrate their range of composition. 
It will be seen that they often carry high percentages of iron oxide 
and that the ratio -j , — -. 
alumina + iron 
and often falls below 2. 
— v^r— rarely rises much above 2. 
Analyses of Carboniferous shales from near Corinth, Md. 
Silica (Si0 2 ) 
Alumina (Al 2 < ) 3 ) . . . 
Iron oxide (Fe 2 3 ) 
Lime (CaO) 
Magnesia (MgO) .. 
Alkalis (K 2 0, Na 2 0) 
Water 
56.42 
20.94 
10. 60 
Trace. 
1.32 
7. 30 
69.51 
22.27 
.80 
Trace. 
Trace. 
Trace. 
7.45 
3 
62. 98 
18. 54 
5.70 
2.44 
.97 
s:> 
51.53 53.49 
22.60 22.83 
6.80 
5.40 
1.87 
11.77 
6.90 
2.91 
1.84 
9.44 
56. 36 
24.18 
6. 40 
.50 
.82 
7.50 
61.70 
22.24 
5. 60 
Trace. 
1.44 
6.50 
56. 32 
23. 00 
5.80 
1.47 
.79 
li. 
1. Red clay (bottom). 
2. Fire clay or flint. 
3. Buff clay. 
4. Bottom blue clay. 
5. Top blue clay. 
6. Cistern. 
7. Railroad clay. 
8. Black shale, coal mine. 
"These analyses are taken from the report by the Maryland geological survey on "Garrett a 
County," pp. 221-222. All the analyses were made by T. M. Price. 
(> Geology of Garrett County, Maryland Geol. Survey, p. 219. 
