Ixvi REPORT OF THE STATE GEOLOGIST. 



the beginning of conditions favorable to the growth of the coal plants, 

 many remains of which are found preserved in the strata. 



MILBURK-STRAWN SERIES. 



Immediately overlying these sandstones and sands and clays we find 

 the Milburn and Strawn series. These beds are composed of alternat- 

 ing clays and shales and thin-bedded limestone with fire-clay and coal. 

 In the Colorado field only one seam is known, and that begins in the 

 southern edge, in a bed of coal shale, which gradually changes to a thin 

 seam of coal as we go northeastward along its strike, until in the vicin- 

 ity of Gordon and Strawn it has developed into a bed of coal of great 

 economic value. 



This difference of condition favorable to the deposits of coal in the 

 two divisions of the Central Coal Field (the Colorado and Brazos) is 

 especially marked throughout the entire series. Thus, in the Brazos 

 field there have been no less than six coal seams observed in the beds 

 which constitute the Strawn Series. These seams of coal, in their 

 southern exposure along the Texas and Pacific Eailroad, show a thick- 

 ness of from one to thirty -six inches, and it is possible that when some 

 of the thinner beds are systematically traced toward the northward 

 along their outcrop that they may also be found to become of work- 

 able thickness. 



The beds of corresponding age to these seem to be wanting in West- 

 ern Texas, except in the Eagle Mountains, and then they are so dis- 

 turbed and faulted by subsequent porphyritic materials that their real 

 position has not been positively determined. 



COAL. 



The coal of the Strawn Division, especially of coal seam No. 1, which 

 has been opened in a number of places along its eastern exposure, is 

 well adapted for fuel purposes. Some of it makes a fine coke in the 

 laboratory, but no systematic attempt has been made to coke it in 

 ovens, so far as our present information goes. 



This coal seam outcrops through Erath, Palo Pinto, Wise, and Mon- 

 tague counties, and can be reached west of its line of outcrop by shafts. 

 The coal is in use upon the railroads and for fuel generally. The other 

 seams of coal in these beds are much thinner, and so far none of them 

 have been observed of workable thickness. * 





