1^9"] ASHLEY — GEOLOGY OF ARKANSAS. 225 



types. Sometimes the ridges can be followed for a score or two of 

 miles ; then again a ridge is prominent only where it approaches a 

 north and south stream, and as it recedes from the stream the 

 valleys on either side become shallower until the ridge coalesces 

 with those next north and south of it, and is lost as a distinct ridge. 



All around the southern edge of the region, the topography is of 

 quite a different nature. It appears to be very level, though having 

 a slight rise to the north. This level strip averages half a dozen 

 miles in width. Its northern edge is irregular and seems to be 

 governed by the erosion of east and west valleys into what might 

 have been its northward extension. Novaculite gravels cover this 

 flat region. Sandstone is the most common rock, though occasion- 

 ally in the valley there are considerable beds of shale. 



It is a matter of common observation among those living in the 

 region, that the rocks almost invariably ''stand on end." 



While much of the region is very stony, the rocks are mostly in 

 the form of loose blocks and boulders, but little of it being found 

 in place and most of that is in the beds of streams. 



Though the strata usually dip to the south, in some places they 

 dip to the north. The dip is usually high, more often over than 

 under 45°. 



Just north of this Carboniferous region are the high hills or 

 mountains of the Ouachita mountain system. The rocks in these 

 mountains are novaculites associated with shales and sandstones.^ 



To the south these Paleozoic beds are overlaid unconformably by 

 sands, marls and limestones of the Cretaceous. 



In the eastern part of the region under discussion the main 

 streams run east or southeast and the branches run south. The 

 streams are not rapid and the valleys are frequently quite broad. 

 Westward the main drainage swings around towards the south, the 

 branches run in east-west channels, and the streams are rapid, with 

 narrow, sometimes precipitous banks. 



From an economic standpoint the most valuable product of the 

 area is the timber. Hard and soft woods of excellent qualities 

 abound in every part of the region. 



Little of value was discovered in the line of building or other 

 stone, nor is the region rich in ores, though small quantities of 

 pay ore, mostly antimony, have been found in the southwestern 

 part of the area. 



Corn and cotton are the principal crops. The country as a 

 whole is well watered and healthful. 



^ Geol. Surv. of Ark. ^ An. Rep, for 1S90, Vol. ili. 



