24 THE PERMO-CARBONIFEROUS RED BEDS OF 



small faulting, which is believed to have taken place almost immediately after the 

 sand was laid down, and before it had been consolidated to any degree. Layers 

 of sandstone i to 4 inches thick are faulted along gently but somewhat irregularly 

 curving lines, which run roughly parallel from a half-inch to several inches apart. 

 The displacement at each little fault is from zero to a half-inch. We have seen 

 such faulting in rapidly accumulated soft mud settling on sloping banks under its 

 own weight, and we have no doubt but that these structures have a similar origin. 

 Their presence in these beds indicates that sedimentation was rapid. In some sands 

 belonging in about the same horizon, and in the same part of the field, were also 

 to be seen some vertical or slightly oblique perforations more or less perfect, seldom 

 more than an eighth of an inch in diameter. These are probably either worm borings 

 of some kind or cavities left by imbedded plant structures. 



Some Larger Bedding Structures. 



"The fact has been mentioned that the sandstone beds can not with certainty 

 be traced for any considerable distance. They disappear, frequently, in less than 

 a mile. Instances of this kind have been referred to in some of the described sec- 

 tions, as in sections 27, 29, 31, 32, 33 [of this paper]. Another case of this kind 

 was noted at a point about 3 miles east of Wichita Falls, where the main wagon 

 road turns up in the low bluff. A silty sand, with a dip that is evidently incidental 

 to the bedding, terminates against a sloping clay surface. The outcrop is some- 

 what obscure. Other cases of dipping sandstones, where the dip is evidently 

 original in the bedding, were noted in survey 27, H. & T. C. R. R. Co., about 6 

 miles south and 2 miles west of Electra. At this point a sandstone runs some 150 

 yards with a dip of several degrees to the east, but on all sides of this place the 

 formation Hes horizontal. Another dip of this kind was noted in the ravines about 

 2 miles south and i mile west of Electra. In a hill facing northeast near the east 

 line of the W. W. Carroll survey, some 5.5 miles north and 4 miles east of Iowa 

 Park, some layers of sandstone, interbedded with red shale, dip some 10 to 15 

 degrees to south and disappear from the outcrop. Close to the south the overlying 

 red shale is capped by some thin, gnarly, black limestone, and this lies horizontal. 

 In all of these cases we believe that the dip is original in the bedding, and in several 

 cases the evidence is clear that an excavation has been made in the accumulating 

 clay and sands, and the dipping beds have been laid down on the sloping sides of 

 the excavation. We believe that these excavations may very well have been made 

 by bottom currents in littoral waters, for there are no evidences of weathering or 

 decay along the contacts on the beveled layers. It is well known that sand banks 

 on the gulf coast are continually undergoing changes, and excavations of several 

 feet may be made more or less extensive in the course of a year. Tidal currents 

 are especially effective in such work. The universal occurrence of cross-bedding 

 in these sandstones, and perhaps also the frequent presence of extensive fiat and 

 thin lamination which we have described, may perhaps be regarded as additional 

 evidence of tidal action. We believe that these sandstones were originally mostly 

 submerged sand-bars, and in some cases sandy beaches. Wave-marks, marks of 

 rain drops, and rill-marks are not often to be seen. It appears to us that these 

 should be more frequent if the greater part of these sands were emerged beach 

 sands. 



CONGLOMERATES. 



"In all the sandstones examined in Wichita County and in the northwest 

 quadrant of Clay County, no quartz grain or pebble was noted which was more 

 than a millimeter in diameter. Coarse ingredients from the same source as the 



