THE GRASS BELT 97 



more and more heavily. The grama now becomes the 

 typical grass; wormwood bushes mingle with it and 

 finally replace it to form a pure * sage-brush ' on the 

 foot-hills. 



The sunk valleys which break the flat or rolling sur- 

 face of the prairies provide the eastern forest vegetation 

 with paths along which it reaches to the heart of the 

 grass- country. Fringing woods accompany the rivers 

 a very long way up, composed of the usual kinds of 

 broad-leaf deciduous trees : oaks, elms, lime-trees, wal- 

 nuts, and hickories, with the robinia-like trees gymno- 

 cladus, gleditschia, and a few others. 



Towards Texas the vegetation is gradually enriched 

 by the appearance of southern plants, which already 

 impress upon the Llano Estacado a stamp quite different 

 from that of the central and northern prairies ; indeed, 

 it belongs to a distinct region. On the east the great 

 treeless plains are not sharply defined from the forest 

 lands of the Mississippi ; it is only gradually that the 

 forests of the central region become poorer, thinner, and 

 more stunted. Islands of trees, then of bushes, lost amid 

 the sea of grass, give the landscape the features of a 

 park, and constitute a belt of so-called ' bush prairie ' 

 round the treeless area. The park prairie extends into 

 Iowa, approaching the Great Lakes, as a sort of bay 

 into the forest region. The banks of streams, the 

 moister hollows, the slopes and foots of the rises, and 

 other favourable localities still retain clumps and patches 

 of deciduous trees throughout this intermediate belt. 

 The most extensive of these tree-islands is thrown 

 athwart the middle course of the Red, Canadian, and 

 Arkansas rivers ; it is known as the ' Cross Timbers ', 

 and covers most of the Indian territory. 



The Great Prairie is the replica of the Great Russian 



1169.1 H 



