284 ASHLEY — riEOLOe^Y OF ARKANSAS. [May 13, 



traced to the Saline river, and, as the structure there is quite different, 

 it will be considered as confined to 5 S., 27 W. Attention is called 

 to the northeast direction of the streams in sections 28-30. 



Sulphur Spring Branch Anticline. — The structure in 5 S., 29 W., 

 is not clear, but the topography and the shales go to show that the 

 Blocker branch axis is followed by the Sulphur Spring branch an- 

 ticline in sections 22-24, ^rid from Harris fork to Baker creek the 

 shale it exposes is a factor in the breadth of the valley of Harris 

 creek. 



In 5 S., 30 W., from Baker creek west, this fold forms a two hun- 

 dred and fifty foot ridge, the structure showing at several places 

 where cut by ravines. In this ridge the shales appear well up in the 

 ridge, while blocks of novaculite lying on the highest point of the 

 ridge indicate the presence of the layer of thin novaculite. 



Reverting to the question of the age of this thin bed of nova- 

 culite, and referring to section 2, PI. ii, it is readily seen that if 

 the novaculite occurring thus on top of this ridge be Lower Silu- 

 rian, as the main body of novaculite is supposed to be, we should 

 have at this point a belt from one to two miles broad in which 

 almost nothing but Silurian rocks are exposed. 



To the west of the Cossatot no anticline was noted in this strike, 

 but it is probable that it influences the topography of Cow creek 

 valley in 5 S., 31 W. 



Harris Creek Anticline. — The Harris creek anticline is crossed 

 by the Saline in 5 S., 28 W., at the north section line of section 

 28. Thence it passes nearly due west, helping to form the high 

 ridge south of Sulphur spring branch, in 5 S., 29 W. It then be- 

 comes part of the Harris creek valley, and is followed by that creek 

 most of the distance. It is crossed by the Cossatot in 5 S., 30 W., 

 at the north section line of section 26. The structure of the fold 

 is well shown where cut by the Cossatot. From this point it trends 

 due west, forming a high ridge for over two miles on the south side 

 of the Cossatot, which, for that distance, flows through a deep nar- 

 row gorge between this ridge and one just north of it made by the 

 Sulphur spring branch anticline. The river flows in the trough of 

 the syncline between these two anticlines, in places being \^alled in 

 by parallel, almost perpendicular layers of sandstone, which give it 

 the appearance of a canal. There is an anticline on this same axis 

 in 5 S., 31 W., section 26, northern part. 



Minor Anticlines. — In 5 S., 28 W., an anticline is crossed by the 



