FUELS AND THEIR UTILIZATION. 



53 









Rio Grande, and consist of clays, sands, limestones, and pebble deposits. The 

 underlying Timber Belt Beds are composed of siliceous sand and greensand 

 marls, interstratified with clays, generally of a brown color, and thin beds of 

 limestone. The beds of lignites contained in both these series of rocks are 

 very numerous, sometimes occurring in lenticular masses of greater or less 

 extent, thinning out in every direction, and again form extensive seams of 

 considerable thickness, frequently fourteen feet. A correct mapping of these 

 deposits has not yet been completed. The Texas Tertiary has been but little 

 disturbed. The force lifting these strata to their present level has caused a 

 gradual and slow elevation, leaving them as originally laid down by the Ter- 

 tiary sea. However, though no violent volcanic eruptions have distorted 

 these beds, they are nevertheless found sometimes broken, faulted and bent, 

 caused by the drying and compression of loose moist underlying deposits. 



CALVEET BLUFF SECTION. 



J 1 



r 

 9 



Fig. 1. 

 Profile of Calvert Bluff, Robertson County, Texas. 



Texas. I. — 1. Brown and red river silt 10 feet. 



2. Gray clay to 3 feet. 



3. Lignite 12 feet. 



4. Gray clay . . ! 2 feet. 



5. Lignite 2 feet. 



6. Gray clay 3 feet. 



After R. A. F. Penrose Jr. 



ALAMO SECTION. 

 II. — 1. Sand and clay 26 feet. 



2. Gray clay 23 feet. 



3. Lignite, black and often glossy 20 inches. 



4. Gray sand 2 feet. 



5. Hard slaty clay 9 feet. 



6. Lignite 4 feet 2 inches. 



After R. A. F. Penrose Jr., Geological Report of Texas, First Annual Report, 1889, E. T. 



Dumble, State Geologist, I, p. 26; II, p. 35. 



The European lignites are of the same geological age, were formed under 

 similar conditions, and consequently they resemble in composition and quali- 

 ties the Texas brown coal. 





