Peneplains of the Ozark Highland. — Hershey. 27 
in extreme southwestern Arkansas and southeastern Indian 
Territory, and rises at quite a perceptible rate toward the 
north. The plain-Hke character is soon lost, and the pene- 
plain is represented by long, narrow ridges whose remarkably 
even crests constitute the remnants of the ancient plain of 
denudation. Still farther north, in Polk and neighboring 
counties of Arkansas, and the adjacent portion of Indian Ter- 
ritory, the ridges with even crest-line have disappeared, but 
the peneplain seems represented in a general way, by the long 
east-west mountains rising 1,200 to 1,500 feet above the gen- 
eral level of the country, and separated by basins five to 
twenty miles wide. Of these ridges, some of the most prom- 
inent are the Push, Rich, Poteau, Cavanal, Sugar Loaf and 
the Magazine mountains. There are many low passes 
through them, and they show a tendency to isolation more 
than the Appalachian ridges. Indee'd, several stand alone, in 
monadnock-like masses, on the Tertiary peneplain. Only in 
a few instances are tlieir summits clearly truncated by a plane 
of erosion base-level. Several of the highest have flats of 
sufficient extent to afford room for farms on the mountain- 
tops, notably the Rich and the Magazine mountains. How- 
ever, there is such a general similarity in hight between con- 
tiguous portions of the mountain system (and neighboring 
peaks) as to leave little doubt that the Cretaceous peneplain is 
approximtely represented by the summits of the Ouachita 
mountains at an average elevation between 2,000 and 2,500 
feet, reaching a maximum of about 2,750 feet on Rich moun- 
tain on the line between Arkansas and Indian Territory, and 
sloping thence very gently to the west and north, and more 
steeply to the east and south. 
Between Cavanal, Sugar Loaf and the Magazine moun- 
tains on the south of the Arkansas valley, and the Boston 
mountains on the north of that broad basin, the Cretaceous 
peneplain has been completely destroyed over a width of prob- 
ably fifty miles, and extending east and west completely across 
the Ozark highland. But it is undoubtedly again represented 
in the Boston mountain at an everage elevation of 2,000 feet, 
reaching a maximum of 2,257 ^cet near Winslow on the S. L. 
& S. F. R. R. Unlike the narrow ridges south of the Arkan- 
sas river, the Boston mountain is a dissected plateau, ten to 
