Geographic Features of the Texas Region. — IJill. 71 
the Red river, extending from the vicinity of Hot Springs, 
Arkansas, through Indian Territory to the 100th meridian in 
Texas, is one of the most important, but least appreciated 
orographic systems in the United States and especially im- 
portant to the Texas region, inasmuch as it is the northern 
limit of most of its peculiar geologic features, and the great 
barrier which differentiates it in every natural aspect from 
the Missouri-Kansas country. In a previous paper I have 
spoken of this as the Ouachita system — a name proposed by 
Dr. John C. Branner, of the Arkansas survey, who, we expect, 
will bring out its details as a result of the careful survey now 
being conducted by him. 
In Arkansas the different parts of this system are known as 
the Rich, the Poteau, the Black Fork, Round Mountain, etc. 
West of that state it includes in its trend the groups locally 
known as the Seven Devils, the Shawnee hills, the Kimishis, 
the Tishomingo, Potato hills, the Arbuckle and Delaware 
mountains, the Witchitas, and the Navajoes — the last near 
the line of the 100th meridian. 
This system consists of several kinds of topography. This 
may be (a) narrow, elevated parallel ridges, with deep interven- 
ing valleys,as seen along the old military road from fort Smith to 
fort Washita, (b) of exceedingly irregular masses, separated 
from each other as in western Arkansas and eastern Indian Ter- 
ritory, and possessing the most erratic outline and extent, as 
beautifully shown upon the contour maps of the United 
States geological surve}', or (c) of low knolls or hills, which 
are so inconspicuous as to be no longer worthy of the name of 
mountains, except from a structural standpoint. The last are 
characteristic of the central portion of the system, in the 
Chickasaw Nation, Indian Territory, near Stringtown and 
Tishomingo where they are known as Potato hills. Again, the 
apparent continuity of the whole system is broken for many 
miles by intervening plains, as between the Arbuckle and 
Witchita mountains. The former eastward continuity of this 
system has beeen destroyed by the erosion of the Mississippi 
embayment — the western end is buried beneath later sedimen- 
tation of the Staked Plain. The eastern and western extremes 
of the system present the most conspicuous elevations. In the 
Arkansas portion the tops of the ridges stand as high as two 
