82 PROCEEDINGS OF THE ACADEMY OF [1892. 



REMARKS ON THE QUANTITY, RATE OF CONSUMPTION AND PROBABLE 

 DURATION OF NORTH AMERICAN COAL. AND THE CONSE- 

 QUENCE TO AIR-BREATHING ANIMALS OF ITS ENTIRE 



COMBUSTION. 



BY ISAAC J. WISTAR. 



The object of this jDaper is to attempt a calculation of the existing 

 quantity of available coal in North America, the present and pros- 

 pective rate of its consumption, its probable duration, and some of 

 the physical consequences of its entire combustion. As much labor 

 has been bestowed on the United States Census returns of 1889,. 

 being the year reported upon in the Census of 1890 ; and as under 

 legislation of unprecedented stringency its officials have enjoyed an 

 unusually favorable opportunity of demanding and obtaining a 

 great number of reports from every quarter of the country, the 

 figures and concluisions of that Census have been followed where 

 applicable, though not without grave doubts that its statements 

 respecting the carboniferous area may be optimistic and excessive, 

 and regret for its silence on the equally imj^ortant subject of thick- 

 ness and quantity. 



The entire carboniferous area of the United States including the 

 post carboniferous beds of Virginia and North Carolina, but exclud- 

 ing the doubtful, much eroded and partly ruined beds of the Eocky 

 Mountain territory, as to which scarcely an estimate is, or could 

 now properly be ventured, is given at 219,080 square miles, being 

 larger than any former estimate. By the carboniferous area is 

 meant, however, not the area of mineable coal or any ap])roxima- 

 tion or reference to it, but the whole of that area over which the 

 rocks of the carboniferous series (excluding the subcarboniferous of 

 geologists), as indicated by their relative position, petrology and 

 fossils, come to find constitute the present surfoce or are within 

 reach of its mining operations. A large proportion of this area 

 never did contain coal, and another portion has long since lost what- 

 ever it once contained, the first in consequence of local failures of 

 the original deposits, and the last because of subsequent foldings 

 and contortions, followed by the erosion and loss of their upper or 

 anticlinal folds. In all parts of the coal fields, areas of original 

 barrenness are extensively interspersed, and in much of the richest 

 coal district of Pennsylvania, the seat of maximum disturbance, and 

 to a less extent, in other portions of the field, minor areas are found 



