110 GEOLOGICAL SUEVEY OF THE TERRITORIES. 



THE COAL SERIES. 



At many points scattered through the formation streaks or indications 

 of coal occur. The only points at which their development has reached 

 financial or commercial success, however, seem to be confined to the 

 lower horizons of the series as exposed near the mountains. These 

 horizons would also be found underlying the plains east of their natural 

 outcrops, and could be reached by artesian borings. How deep these 

 borings would have to be, however, to penetrate to the coal horizon be- 

 neath the plains, sufficient examination has not yet been made to deter- 

 mine with any degree of certainty ; and even if reached, it is by no means 

 certain, though quite probable, that coal would be found to exist in the 

 same workable quantities as nearer the mountains. 



CHAEACTEES AND APPLICATIONS OF THE LIGNITIC COALS. 



Chemical characters. — The name lignite would imply that these coals 

 were allied to the brown coals of Europe, a relation indicated by the large 

 percentage of water, usually above 12 per cent., which they contain. At 

 the same time this amount of water is small as compared with that of most 

 foreign lignites, while, instead of having a fibrous or woody structure, 

 they are compact, and generally have a very black color and high 

 shining luster, thus more resembling some bituminous coals. The per- 

 centage of ash for lignites is also low, varying from 2 to 6 per cent., while 

 sulphur seldom reaches 1 per cent., and is often nominally absent. The 

 *' volatile products" evolved from coal below a dull red-heat usually 

 vary from 25 to 37 per cent., while the amount of "fixed carbon'' gen- 

 erally lies between 45 and 60 per cent., these two components repre- 

 senting approximately the calorific or heat-producing power of these 

 coals. The above characters would seem to indicate that these coals are 

 superior to those foreign coals from which the term lignite has been de- 

 rived. Since, on the other hand, they differ in some respects from bitu- 

 minous coals, and since their extensive occurrence in the West requires 

 some convenient term which will express to a certain extent their char- 

 acter, I have seen fit to use the term lignite coal or lignitic coal. 



It has been necessary to thus separate these coals as above into the 

 four principal ingredients — water, ash, volatile products, and fixed 

 carbon — because nearly all the analyses of them that I have been able 

 to find thus separate them. While such proximate analyses, as will be 

 X)oiuted out shortly, do not give sufficient data for estimating closely 

 the actual calorific value of these coals, and would therefore be mis- 

 leading in comparing them with bituminous and other coals, they yet 

 serve, to a certain extent, to compare these lignites among themselves ; 

 indeedj they form the only data for such comparisons at the present 

 time. 



With this end in view, I have gathered together in the following table 

 all the trustworthy proximate analyses that I have been able to find. 

 They are arranged geographically, commencing in New Mexico and 

 proceeding northward along the eastern base of the mountains through 

 Colorado to the line of the Union Pacific Eailroad in Southern Wyoming, 

 thence westward along this line to Utah, then proceeding northward 

 along the Pacific coast, and ending finally with a few localities near our 

 northern boundary. For better comparison, the localities within my dis- 

 trict are printed in small capitals, and are included in the group between 

 the two heavy lines. All the analyses give the percentages of the com- 

 ponents as calculated upon the coal as taken from the mine — that is, 

 including the moisture — except those with the reference "^" attached, 

 in wliich the percentages are calculated on the dried coal ; that is, after 



