XXXVI REPORT OF THE STATE GEOLOGIST. 



facts concerning them as would enable the owner or prospector to form 

 any definite idea of their relations or probable values. 



The following statements are based for the greater part on the wnrk 

 of myself and associates of the present Survey (although all reliable 

 sources of information accessible to us at present have been examined), 

 and many of the facts will be found stated in much greater detail in 

 the various papers accompanying this and preceding Annual Reports, 

 to which the reader is referred. 



FUEL AND OILS. 



WOOD. 



Over Eastern Texas the amount of wood suitable for fuel purposes 

 is seemingly inexhaustible ; but as we go west it grows less and less, 

 until in many places mesquite roots or even the " Mexican dagger " are 

 the principal source of supply. The investigations of the Survey up to 

 the present have been confined to an examination of the wood supply of 

 certain counties with reference to the manufacture of charcoal for iron 

 smelting, and this will be more fully discussed in Part II of this Re- 

 port, "Report on the Iron Ore Region of East Texas." Other facts are 

 also given in other parts of the Report. 



LIGNITE. 



Intermediate between peat and bituminous coal we find a fossil fuel 

 known as lignite or brown coal. It contains less water and more car- 

 bon than peat, but has more water and less carbon than bituminous 

 coal. Lignites are the product of a later geologic age than bituminous 

 coal, and the bituminous matter has not been so fully developed as in 

 the true bituminous coal. 



Lignite varies in color from a brown to a brilliant jet black, and oc- 

 curs in all degrees of purity, from a lignitic clay to a glossy coal of 

 cubical fracture. The greatest amount of our lignites, however, are of 

 black color, changing to brownish black on exposure, often with some- 

 what of a conchoidal fracture and a specific gravity of about 1.22. 



Lignite occurs in beds similar to those of bituminous coal, although 

 they are not always as regular and continuous. 



Localities. — The area in which the lignites occur in Texas was de- 

 fined in general terms in the First Report of Progress, p. 20, as follows : 



" The lignite field is by far the largest field we have, and the coal strata it 

 contains are of much greater thickness than those of either of the others. As 



