(general Xotcs. 



GEOLOGY AND PALEONTOLOGY. 



The North American Coal Supply. 1 — General Wistar's dis- 

 cussion of the North American Coal Supply has been published by the 

 Phila. Academy. The author first calculates the existing quantity of 

 available coal in North America, the present and prospective rate of 

 its consumption, its probable duration, and some of the physical conse- 

 quences of its entire combustion. The figures and conclusions of the 

 United States Census returns of 1889 have been followed, modified 

 somewhat by the author's personal observations. 



"The entire carboniferous area of the United States, excluding the 

 broken Rocky Mountain territory is given at 219,080 square miles. 

 A large proportion of this area, however, never did contain coal ; and 

 there are minor areas where more than two-thirds of the original beds 

 have been carried away along with the adjacent protecting rocks and 



Again, much of the coal possesses no economical value because of its- 

 crushed and impaired condition, its detached position in small basins,, 

 and to the thinness of many beds. These reductions may be con- 

 sidered to offset the following items not considered in the Census 



1. The detached basins in the Rocky Mountain territory. 



2. The inaccessible coal of the arctic and tropical regions. 



3. The relatively small beds of Nova Scotia and British Columbia. 

 Assuming then, the area, 219,080 square miles, as the area of 



mineable coal, the author discusses at length the data for calculating 

 the average thickness and arrives at the conclusion that six feet is an 

 admissable working estimate. This gives 219,080 square miles re- 

 duced to acres multiplied by 6 feet (of thickness) and by 800, being 

 the available tonnage per foot of thickness from each acre, would 

 give the tonnage, which is 673,013 millions of tons. 



The same Census report states the consumption during the year 

 1889 at 126,097,779 tons, and the increase of consumption to have 

 been at the rate of 100 per cent, per decade. From these figures the 



^Remarks on the Quantity, Rate of C «^^°*££ ^mafs^t " 



