108 JOURNAL OF THE ARNOLD ARBORETUM (vol. t 



THE LIGNEOUS FLORA OF RICH MOUNTAIN, ARKANSAS 



AND OKLAHOMA 



Ernest J. Palmer 



That part of the Ozark region lying south of the Arkansas river, using 

 the term Ozark in its broadest application to include all of the elevated 

 and serai-mountainous country between the Mississippi lowlands and the 

 Great Plains, comprises two rather distinct sub-regions, differing from 

 each other in topography and geologic structure, as likewise from the more 

 typical mountain and plateau sections to the north. On the eastern side 

 in south-central Arkansas, the name Ouachita Mountains has been applied 

 to a series of low hills separated by narrow rocky valleys, formed upon a 

 varied series of early Paleozoic rocks ranging from shales, sandstones and 

 quartzites to massive novaculite chert. These strata have been broken 

 up, tilted and folded in a complex manner, and in places masses and dikes 

 of eruptive rocks have been forced into them. Farther west in Arkansas 

 and extending into eastern Oklahoma very different conditions are en- 

 countered. Here the mountain-making movements of late Cretaceous 

 time, although probably connected with other disturbances on a larger 

 scale beyond our area, seem locally to have spent their force in a series of 

 radiating or parallel lines of faulting and upheavals, while leaving con- 

 siderable sections of the country but little disturbed. The different nature 

 of the strata encountered here, consisting of heavily bedded sandstones 

 alternating with shale and occasional layers of coal and clay partings, 

 of the Pennsylvanian series, has resulted after a long period of erosion in 

 a quite distinct topography. The traveler entering this country from the 

 north, after crossing the Boston Mountains in western Arkansas or skirting 

 them in eastern Oklahoma, will be impressed at once with the change in 

 the landscape. Instead of an extremely rugged country with a close 

 alternation of hills, ridges and narrow valleys, all rather heavily wooded 

 and with but little evidence of civilization or settlement, he here finds 

 broad open spaces and rivers flowing not through wide alluvial valleys, 

 except in the case of the Arkansas, but through level uplands of moderate 

 elevation, many miles in extent, sparsely wooded and dotted over with 

 villages and farms, while on all sides can be seen on the horizon the outlines 

 of more or less distant ranges or isolated peaks and domes of conical or 

 long canoe-shaped mountains. 



Thomas Nuttall, the English naturalist, who came up the Arkansas 

 river in 1819, and who was the first scientific traveler to visit this section, 

 described the park-like aspect of the country in its then primitive condi- 

 tion, with its alternation of grassy prairies and groves of small trees, 

 amongst which great herds of antelope and deer were grazing, and with 

 buffalo and bear abundant at no great distance. In his Journal of travels, 

 published in Philadelphia in 1821, there are also illustrations, from sketches 

 made by the author, of several of the prominent mountains, including 



