242 THE IRON ORE DISTRICT OF EAST TEXAS. 



lies, as chlorides, 6.26; manganese dioxide, undetermined; phosphoric acid 

 and sulphur, traces. Some two miles south, or within five hundred feet of 

 the depot at Beckville, the same burned and disturbed clay was seen without 

 scoria in a road bed; strike apparently northwest and southeast; dip at one 

 place sixty degrees southwest, but within one hundred and fifty feet the dip 

 changes to north by east and disappears under the surface soil and under a 

 ridge on the north. On the summit of the ridge under which the burned 

 clay disappears were seen fragments of silicified wood, with adhering crystals 

 of quartz; also fragments of iron sandstone. A well forty feet deep from the 

 top of this ridge passes through alternating beds of sand and clay, and 

 through the lignite bed, which is here about four feet thick. (It has been 

 before remarked that the water bearing sand overlies the lignite bed. This 

 was conspicuous in the Mineral Spring lignite bed, where the water forms 

 dripping springs in the tunnel, carrying down considerable quantities of fine 

 white sand into the crevices of the lignite on the sides of the tunnel.) The 

 wells are often dug into o*r through the bed of lignite to form catch basins 

 for holding a supply of water. 



Three miles southwest of Mineral Spring Ridge is another ridge, rising 

 from Twoomy Creek or one of its tributaries, in which was reported a cave 

 from which specimens were taken by early prospectors and reported to have 

 assayed silver. The locality was visited and proved to be a prospect hole 

 (then full of water) on the side of the ridge, from which a quantity of meta- 

 morphic clay quartzite had been thrown out at the time of the digging. This 

 was similar material to that of the Twoomy Creek railway cut. An assay in 

 the laboratory showed no silver except that usually found in the oxide of 

 lead used in making assays. This may have misled some former assayer in 

 making the analysis. 



The stratum of baked and burned clay having been observed at three dif- 

 ferent points of a triangle having sides several miles long, indicates a consid- 

 erable area of disturbance accompanied with metamorphism. Its character, 

 even where least burned, is quite different from the ordinary clays of the 

 Tertiary, while its stratigraphic position, as seen dipping under the lignite at 

 Beckville, shows that its deposition and disturbance was prior to the forma- 

 tion of the lignitic series, and must belong therefore either to the earlier 

 Tertiary, or possibly to the later Cretaceous. The large percentage of lime 

 (ten per cent) from the analysis of the scoria or cinder would rather point 

 to a close connection with the latter. The least burned, or yellow baked 

 • clay, however, contains only one and two-tenths per cent of lime, combined 

 with its equivalent of silica as silicate of lime. 



