OUR COAL LANDS 



447 



HE POINTS TO COM, 



The huge Triceratops of the Wyoming Basin, 25 feet long by 10 feet tall, is, where found, 

 a good lead for the coal geologist. His remains, however, are too scarce to be depended 

 upon. 



Where the coal geologist finds this conch 

 in a rock formation he knows that no 

 coal beds will be found lower down in 

 the ground. He knows that some coal 

 may be found in the same strata in which 

 the conch lies, but that in the strata im- 

 mediately above very high-grade coal can 

 be confidently expected. The name of 

 this little helper of Uncle Sam, who was 

 a very abundant resident of the early 

 United States, is Pyrgulifera humerosa. 

 He hasn't any American name. 



In this coal classification and valuation 

 work, which is the next economic step 

 following the discovery of the coal beds, 

 the geologist comes down out of the 

 realm of high science, with its Pyrguli- 

 feras and other things, right into camp 

 with the every-day coal miner and oper- 

 ator. Using the data which the geolo- 

 gists bring in from each field season's 

 work in Wyoming, Montana, Utah, and 

 all the other public coal-land States, the 

 Geological Survey at Washington works 

 out the tonnage on everv 40-acre tract of 

 coal land, and, taking into consideration 

 the quality and depth of the coal, places 

 a valuation upon the land. 



This valuation ranges all the way frotn 

 $TO an acre up to several hundred dol- 

 lars. Some of the land, where the coal 

 seams are very thick, of high-grade coal, 

 or where there are several seams, one 



over another, has been rated at over $400 

 an acre. 



This seems like a big price — $64,000 

 for a 160-acre tract of coal land which, 

 until the coal-land classification work be- 

 gan, in 1906, was sold at $20 an acr:, 

 or $3,200 — but, when it is seen whit a 

 great amount of coal an acre of such land 

 contains, even the $400 -valuation looks 

 small. 



Many of the western coal lands are 

 underlain by beds of 40, 50, and even 

 aggregating 100 or more feet of solid 

 coal. An acre of coal 40 feet thick con- 

 tains 72,000 tons, and the Geological Sur- 

 very calculates that at least 40,000 tons 



FOSSIL SHELL OF A SMALL CRETACEOUS 

 CONCH, PYRGULIFERA HUMEROSA 



A most useful geologic key to the western 

 coal beds 



