146 
TRUE COAL MEASURES. 
beds,—some whose thickness is measured 
by many feet,—existing over one another, 
in the actually explored districts of our 
coal formation. 
The interval between the old red sand¬ 
stone or Devonian and the new red sand¬ 
stone, is therefore entitled by way of 
eminence to the title of carboniferous^ from 
the great predominance of the matter of 
coal within its minor successions. 
