COAL MEASURES. 251 
Section of Coal Hill, Pittsburg, Pa, 
Fig. 47. 
Feet. 
20 ^^^^^^ 1- Reddish hrown argillaceous earth, 
30 : ^ 2. Sandstone — slaty, fine-grained, 
^ ash-coloured. 
^^^^^^M 3. dark brown, carbona- 
^ ceous, slaty. 
4. Clay — dark-coloured, carbona- 
ceous. 
5. Coal — bituminous ; supplies 
the manufactories of Pitts- 
. burg. 
^VSVii^^v^^ ^- ^^^^ — ^^^^> slaty. 
7. Sandstone, 
^ 8. Limestone — dark-coloured. 
^ 9. Sandstone — light- coloured and 
argillaceous, witlx impres- 
sions. 
10. Limestone — light-col'd, hard, 
^ compact. 
11. Sandstone — fine-grained, com- 
pact, gopd building-stone. 
Salt water is obtained by 
boring through this rock. 
270 
