172 STEVENSON— INTERRELATIONS OF THE FOSSIL FUELS. 



Siberian resources"'*" states that south-southwest from the Irtych 

 River a thin bed of hgnite was seen, which retains the woody texture 

 and contains grains of amber. Lignite-bearing Tertiaries are of 

 notable extent in the Transbaikal region ; they are later in origin than 

 the present topography of the country; the rocks show leaf impres- 

 sions and contain silicified stems of dicotyledonous trees. The lignite 

 beds are 2 to 4 meters thick but are lens-like, thinning away at the 

 borders. 



Some Chemical Features of tJie Tertiary Coals. — The literature 

 dealing with the chemistry of Tertiary coals is voluminous, but 

 comparatively little of it is serviceable for the present study. An- 

 alyses, for the most part, are of coal from localities where the fuel 

 values had been proved long before the analyses were made : com- 

 paratively few are from deposits which are not important econom- 

 ically. In the United States and Canada, the samples are prisms 

 from the whole face of a bed, only such partings being removed as 

 should be separated from the coal before shipment. Analyses of 

 such samples afford no clue to the varying conditions during accumu- 

 lation of a bed. It is well understood that a proximate analysis of 

 coal containing a high percentage of water yields at best only ten- 

 tative results, varying in any case with the temperature employed. 

 Ultimate analyses are, from the geologist's standpoint, little better, 

 since coals of wholly different types may have practically the same 

 ultimate composition, as was shown by Carnot. Coals are apparently 

 mixtures of various hydrocarbons, respecting which very little is 

 known, as only a few of them are acted on by solvents. But one 

 must make use of the material within reach and much can be learned 

 by comparison of analyses made after the same method ; the official 

 laboratories in the United States afford abundant material. 



In studying the mature deposits of peat, known as Schieferkohle, 

 V. Giimbel discovered a dopplerite-like material, which had saturated 

 the mass and had become insoluble. A similar substance is in brown 

 coal. Glockner-*^ examined the black lustrous coal, with conchoidal 



240 Le Comite Geologique de Russie, " Apergu des Explorations geolo- 

 giques et minieres le long du Transsibirien," St. Peterbourg, 1900, pp. 42, 68, 

 87, 123, 153- 



-■*! Fr. Gltickner, " Ueber Zittavit, ein epigenetische, dopplerit-ahnliches 

 Braunkohlengestcin," Zcitscli. d. d. gcol. Gcscll., 191 1, pp. 418, 419. 



