HOW IS COAL FORMED? 
53 
I am told that other mines do not differ much 
from the one which I visited, except that in many 
parts of the world they are much farther below the 
surface. Kow you will want to ask, “How is coal 
formed ? ” 
HOW IS COAL FORMED? 
If you will go to the coal-yards you can in a few 
minutes, no doubt, tind a number of pieces on which 
are distinct impressions 
of leaves or stems of 
plants. In some mines 
there are found stumps 
and logs changed to 
coal. 
If we examine thin, 
prepared slices of coal 
with a microscope, we 
can discover vegetable 
cells and fibers ; in pure 
specimens we can find 
even the blossoms and 
fruits of trees. 
Lyell, a great Eng¬ 
lish geologist, found in 
one place seventy-three 
tree stumps in an area 
of a quarter of an acre. 
Some of these were no 
less than two and a half feet in diameter, and one 
log was thirty feet and another fifteen feet in length. 
5/ 
boniferous sandstone. 
