2 Illinois Natural History Survey Circular 49 



been cultivated or they have been taken over for housing or indus- 

 trial developments; we must rely on old collections of plant and 

 animal specimens to document the unusual life that formerly occurred 

 in them. 



One area of sand deposits is still well preserved in its wild state. 

 This is the strip of sand ridges and marshes extending from Wau- 

 kegan northward along the shore of Lake Michigan into Wisconsin, 

 fig. 1. Part of this unique area in Lake County, Illinois, forms Illinois 

 Beach State Park. In the following account, the Illinois strip of Lake 

 Michigan shore north of Waukegan, including Illinois Beach State 

 Park, is called the Dunesland, the name given by the naturalists who 

 have long been appreciative of this historic wilderness remnant. 



Both the topography making up the Dunesland and the peculiar 

 combination of plants and animals that constitute its life are the 

 result of events dating back into remote stretches of time. Attempts 

 to unravel this history make a fascinating study. 



At first glance, much of the Dunesland, fig. 2, looks like an 

 ordinary marsh or prairie such as those occurring alongside many 

 miles of railroad tracks throughout Illinois. However, as soon as the 

 particular kinds of plants and animals growing and living in the 

 Dunesland area are identified, it is clear that this superficial resem- 

 blance is deceptive, because the Dunesland contains a remarkable 

 biological assemblage found in no other part of Illinois. 



Species unusual for Illinois are found in all parts of the Dunes- 

 land. The two native junipers, fig. 3, and bearberry, fig. 12, grow on 

 the open sand ridges. The dwarf birch and the roundleaf dogwood 

 occur along the edges of the swales. Several kinds of unusual orchids 

 and gentians grow in the meadowlike marshy areas. Each of these 

 plants is found in some other locality in Illinois, but nowhere else 

 do all of them grow in such profusion on one small area. The unusual 

 feature about all of these plants is that they are typically northern 

 species. Most of them are common from the Atlantic to the Pacific 

 coasts in more northerly regions of the United States and adjacent 

 parts of Canada. The Illinois occurrence of each of these species 

 represents the southernmost edge of its range in the central part 

 of the continent. 



The particular combination of plants found in the Dunesland 

 does not occur in other prairies and marshes situated only a few miles 

 west of Lake Michigan, where the climate is presumably almost 

 identical with that in the Dunesland. This circumstance indicates 

 that there is some other ingredient in addition to climate that is 

 responsible for the peculiar combination of living things found in the 



