their range in the IlHnois sand areas. Others are not continuous in 

 distribution, but occur in the sand areas and also in the West. Others 

 may have been isolated in the Illinois area, and have become distinct 

 geographic varieties. Enough has been said to show that the sand 

 areas of the Illinois River and similar sand deposits in other parts of 

 the state are in reality local eastern extensions of the sand-hills of the 

 middle region of the prairie province, or, what is nearer the true state 

 of affairs, relic colonies of sand prairie, surrounded by the typical 

 prairie-grass and forest formations of Illinois. 



In addition to the xerophytic relic colonies in Illinois, other regions 

 characterized by severe physical conditions point toward the former 

 presence of the eastern extension of the arid prairie. The western 

 element gradually fades out toward the east, and is best developed in 

 the most barren habitats. This element is well represented in the 

 flora and fauna of the sandy shores of the Great Lakes. Jennings ('08 

 and '09) records from the sand-plain of Cedar Point and Presque 

 Isle, two sand spits in Lake Erie, such western plants as Opiintia rafi- 

 nesqiiii, Andropogon spp., Artemisia caudata, and Panicum virgatum 

 and scrihncrianiini. A larger number of western plants, and a very 

 considerable number of western animals, are found at the lower end 

 of Lake Alichigan. Several sand regions occur in Indiana, the most 

 extensive being the Kankakee River valley sand area. The principal 

 sand areas in Illinois, aside from the Havana and Lake Michigan 

 regions, are the Kankakee area, along the Kankakee and Iroquois riv- 

 ers in eastern Illinois ; the Amboy area, on the Green River, in Lee 

 county, in which very little sand prairie is left; the Dixon area, in 

 Lee county ; the Winnebago county area, now mostly forested ; and 

 the Oquawka area and the Hanover area along the Mississippi, in 

 which very extensive tracts of sand prairie are found. 



Western relics are found on the xerophytic sandstone outcrops in 

 La Salle county along the Illinois River, and in Ogle county along the 

 Rock River. The outcrop of Sioux quartzite in northern Iowa fur- 

 nishes xerophytic conditions of plant growth, and in a report on its 

 flora, Shimek ('97) records Opiintia, Buchloe, Chrysopsis, Boitte- 

 loua, Sporobohts, and other plants of western derivation. All these 

 colonies of plants and animals, a large number of which are derived 

 from the sand prairie, indicate the former presence of arid conditions. 



