PAPERS ON BIOLOGY AND AGRICULTURE 79 



PRELIMINARY REPORT ON THE BOGS OF NORTH- 

 ERN ILLINOIS 

 Prof. W. G. Waterman, Northwestern University 



It is a fact not generally known to the public at large and 

 even to the botanists of the state that in Lake County there 

 are several bogs, small in size but possessing the character- 

 istic vegetation and conditions of similar formations usu- 

 ally found much farther north. While these bogs may have 

 been mentioned in local statements, so far as known to the 

 writer, no technical description of them has appeared in 

 print. This report is based on a superficial survey with the 

 expectation of a more detailed study of environmental con- 

 ditions and a discussion of suggested problems later. 



So far seven bogs have been located and it ia probable 

 that there are others, although the conditions necessary for 

 the production of bogs may be found only in Lake County 

 and not in other parts of the state. These seven bogs are 

 all within the limits of the Valparaiso moraine which is 

 characterized by a soil consisting of clay or gravel, fre- 

 quently containing a large percentage of calcium carbonate, 

 and having an uneven topography, originally with many 

 knobs and kettle holes. Most of these depressions have been 

 included in the drainage systems of the rivers of the region, 

 but a section in western Lake and eastern McHenry 

 Counties on the divide between the Fox and DesPlaines 

 Rivers still contains a few poorly drained or undrained de- 

 pressions, and it is in these that the bogs are found. It is 

 probable that bogs were formerly very numerous, as indi- 

 cated by the many patches of deep peat shown on the soil 

 map of Lake County, although of course peat is formed by 

 swamp vegetation as well as by bog plants. These bogs are 

 interesting, first, as furnishing the only specimens of bog 

 types of vegetation to be found in Illinois, and second, as an 

 illustration of the method by which many of the patches 

 of deep peat have been formed. 



As these bogs are found in Lake County approximately 

 from ten to twenty miles west of Lake Michigan, the gen- 

 eral climatic conditions are similar to those of Chicago and 

 vicinity, but on the whole probably more extreme, and of 



