1897.] ASHLEY — GEOLOGY OF ARKANSAS. 265 



overthrow is to the north, of the type G'H', Fig. 13, and an ap- 

 proximate correlation of strata is possible. In the northern part of 

 township 6 S., ranges 19 to 22 W., is a long shale valley just north 

 of the Chalybeate mountain, occupied to the east by De Roche 

 creek, further west by the Caddo river, and still further west by 

 Brushy creek. In various parts of this valley there is much indi- 

 rect evidence of an anticline or overturn, but, aside from those 

 mentioned above, at only two places was direct evidence obtained, 

 and that was not very satisfactory. In 6 S., 20 W., section 10, 

 near the northwest corner is a round mound 80-100 feet high giv- 

 ing a dip of 75° N., 7° E. on the north side and 60° S., 2° W., on 

 the south sidej and in 6 S., 21 W., northeast quarter of section 

 12, at the bend in the Caddo there is some appearance of over- 

 turning. Scattered perpendicular dips in shales on. about the same 

 line would suggest that an anticline or overturn passed through the 

 two points mentioned. 



Western Portion of the Caddo River Valley. 



In this division the structure is in several cases well displayed by 

 anticlinal ridges which rise sharply from the broad valleys here 

 predominating. The structures in these broad valleys is obscure, 

 as might be expected, and in some portions the shale and in- 

 terbedded sandstones have been twisted, faulted and jammed to- 

 gether until they defy all attempts to work out the original struc- 

 ture. 



In 5 S., 22 W., Dr. J. P. Smith reports^ four anticlines north of 

 the Caddo river, the most southern of which is probably the same 

 as the overturn giving the novaculite ridge north of Rock creek. 

 It is probably this anticline which appears at the bend of the 

 Caddo in 5 S., 23 W., section 17. 



Sugar Loaf Creek Anticline. — In 5 S., 23 W., in section i or 

 2, near the section line, on Sugar Loaf creek is one of the few ex- 

 amples of an anticline where the axis is exposed, showing the beds 

 closely bent on themselves. This exposure occurs at a road cross- 

 ing where the creek makes a sharp turn to the east. It may be a 

 continuation of one of the anticlines found by Dr. Smith. 



Caney Fork Anticline. — In 5 S., 23 W., at the bend of the Caddo 

 in section 11 is another case of an overturn showing well in the 



^ Geol. Siirv. of Ark. ^ Rep. for 1 890, Vol. iii, Mount Ida sheet. 



