1897.] ASHLEY— GEOLOGY OF ARKANSAS. 277 



and the evidence of an overturn here are somewhat stronger, chiefly 

 the presence of shales with north and south dips. In the southern 

 part of section 27, on the west bank of Antoine creek, a long bluff, 

 seventy-five feet high, gives an excellent exposure of rock, and on 

 either side of one point the layers bend toward each other in such 

 a way as to suggest the axis of an overturn. Bluff mountain, a 

 quarter of a mile farther south, also gives a fine exposure. An 

 anticline probably crosses the big river-bottom in section 34, 7 S., 

 23 W. 



In 7 S., 24 W., high dips and a ridge one hundred feet high, 

 crossing Wolf creek near the centre of section 21, suggest the 

 probability of an overturn with a strike S., 70° W. This is in the 

 strike of an overturn on Prairie creek, to be described later. 



VII. Detailed Structure on the Western Sheet. 



Township 4 South. 



Rachel Mountain Axis.— 'R.SiChtX mountain is a novaculite ridge 

 in the northern part of 4 S., 30 W., and has been described in the 

 report on novaculite.^ Its axis crosses the Brushy Fork of the Cos- 

 satot in 4 S., 30 W., section 5, southwest quarter. It ceases to be 

 a novaculite ridge before reaching the Brushy Fork. In the same 

 strike in 4 S., 32 W., section i, half a mile south of Cove, an anti- 

 cline is crossed by the line road, and traces of it are found in 4 S., 

 31 W. 



Buffalo Creek Anticlinal Axis. — This axis is reported by Mr. 

 Means- as crossing the Brushy Fork in 4 S., 30 W., section 7, the 

 southwest quarter, near the mouth of Horn creek. 



In 4 S., 31 W., it was noted again in section 12 and in section 

 10; the presence of igneous rock and the topography across that 

 row of sections suggest its continuity in a due west direction. 



In 4 S., 32 W., Mr. Means found the axis crossing the Old Line 

 road near the middle of the section line between 11 and 12. A 

 few uncertain dips indicate that it continues westward, and that it 

 determines the Buffalo creek valley. 



1 Geol. Surv. of Ark., An. Rep. for 1890, Vol. iii, p. 262. 



2 Mr. J. H. Means, assistant geologist of this survey, worked up considerable 

 of the area included in 4 and 5 S., 30 and 32 W. Most of the structure in 30 

 W. was gone over to get its connection and relation to the structure further east. 

 That in 4 and 5 S., 31 and 32 W., is largely taken directly from Mr. Means' 

 notes. 



