■895-] 487 [Marbut. , 
Tvestward it is continued in what I have called the " Malvern 
Ridge" and the Tertiary uplands north of Red River in 
western Arkansas. All these features are shown diagrammati- 
cally in Fig 1. 
The fact that Crowley's Ridge and the lowland along its 
western side are parts of continuous features lends suppoit to the 
view that they were all similarly developed, and the close relation 
of the whole to the ideal scheme, with some local variations, 
lends support to the view that they were all developed according 
to the scheme. 
One of the variations of the scheme is the course of White 
River along the lowland. Instead of turning northeastwardly 
on entering the lowland Ijelt and flowing into the Mississippi 
River at the head of the embayment, it turns southvv^estward and 
gradually southeastwardly and flows into the Mississippi south 
of the ridge. Its course suggests a southward diversion by 
capture by some stream to the south of it. The only stream 
at all capable of doing it is the Arkansas, a stream smaller than 
the ]VIississipj)i at the bead of the embayment. Two things may 
have aided the Arkansas in doing this: 1. The constructional 
slope of the embajaiient on this side was to the southeastward. 
2. The hard member (the lignitic) of this part of the coastal 
plain was evidenth^ much less resistant here than elsewhere. I 
am, however, not pre]>ared to say that the present lower course 
of White River is not its constructional course. 
Some features of the lowland west of Crowley's Ridge and 
of the ridge itself seem to imlicate that no large stream evei- 
flowed around west of the ridge. These are the nature of the 
lowland, and the attitude of certain streams. 
The lowland is more than 40 miles wide at the southern 
end of the ridge, but northwardly its \vi<lt]i decreases gradually 
to Stoddard County, Missouri, where it is not more than Ave 
miles wide. If it were a part, now abandoned, of the flood- 
plain of a large stream, it would have approximately the same 
width along its whole course unless there were a considerable 
difference in the resistance of the rocks at different places, but 
here the strata making up the ridge seem to be least resistant 
just where the lowland is narrowest. 
