KANSAS CITY REVIEW OF SCIENCE. 



GEOLOGY. 



TERTIARY COAL MEASURES OF GUNNISON COUNTY, COL. 



JOHN K. HALLOWELL. 



Some time since, a communication in the form of a query was published in 

 the Denver and Gunnison papers over the signature of Charles Henry Baker, M. 

 E., asking, in reference to the coal found in that county, "Is it anthracite?" 



I send you the following, thinking it may help to settle the question, as well 

 as give some additional information of possible practical value; this being the re- 

 sult of personal observation during a close examination lasting nearly five months, 

 spent in and around these coal measures, with a view to determine their age, 

 structure, and, in a measure, their commercial value, as seen locally and in com- 

 parison with data obtained from other sections. 



The first five years of my geological work being among the coal measures of 

 Missouri and Kansas, I have always been much interested in what had been 

 brought to me in the way of specimens from the Gunnison country coals. For 

 two years these specimens had come, the parties having the same claiming the 

 product to be anthracite. This I disputed, as no one could inform me of any 

 change in the connecting rocks that showed an opportunity for a change in the 

 coal, by metamorphism, from a bituminous coal to an anthracite. In fact, I con- 

 sidered {without tests) that the appearance of the specimens was, in gravity, 

 fracture, and luster, against such a result. The coals appeared more like the 

 Albertites of Nova Scotia, or a coal highly charged with bitumen. On the other 

 hand, the chemists' analyses shown me gave such high results in fixed carbon that 

 it must be rated as an anthracite ; and if the latter, the rocks accompanying the 

 coal-seam must show a corresponding change. As stated, of this none could tell 

 me, and, as a geologist, I must confirm what the chemist had shown or find out 

 the reason why. 



The geological structure of this coal measure formation, as seen by myself in 

 the Crested Buttes and Ohio Creek basins, was a revelation, as nothing like it is 

 known or described in any works that I have; many things appeared to be re- 

 versed and not at all analogous to other known localities where coals occur. So 

 great was this difference that I must give the facts as seen by an ordinary observ- 

 er, and then try correctly to describe the geological structure, adding thereto a 



