268 



NATURALIST'S GUIDE TO THE AMERICAS 



niul St. I'aul. They give to these 

 portions of the state a rolling or even 

 hilly aspect. 



\ very .striking feature of the Minne- 

 sota landscape is the numerous glacial 

 lakes estimated to number about 10,000 

 and ranging in size from a few acres in 

 area to large l)odies of water 15 to 35 

 mi. in exjianse. Together with the 

 streams and rivers these lakes give 

 Minnesota a greater fresh water area 

 than any other state in the Union, 

 amounting to approximately 5637 sq. 

 mi., without including Lake Superior. 

 These lakes can l)e divided into three 

 classes as follows, depending upon the 

 nature of the topography of the region 

 in which they are situated: 



1. Lakes of morainic till areas. 



2. Lakes of modified drift areas. 



3. Lakes of bare rock areas. 



The first class is the most numerous 

 embracing about three-fourths of the 

 total number. The most remarkable 

 of these areas is that of the Leaf Hills 

 of Becker and Otter Tail counties 

 where nearly half of the surface is cov- 

 ered l)y water. This area extends in a 

 southerly direction to Douglas, Carver, 

 Hennepin and Le Sueur counties and 

 northward to Clearwater, Beltrami, and 

 Itasca counties. The second class em- 

 braces the largest lakes of the state 

 including Red, Mille Lacs, Leech, 

 ^^'innibigoshish, and Cass Lakes. They 

 are for the most part shallow and are 

 situated on extensive outwash plains or 

 otherwise modified drift. The third 

 class embraces the lakes of rocky basins 

 and are mostly confined to the north- 

 east corner of the state which was 

 subjected to the severest glaciation. 

 These lakes are very numerous. They 

 are usually long and narrow with tor- 

 tuous and bold shores. Many are of 

 considerable depth and they are fre- 

 quently connected by swift flowing 

 streams. 



Drainage systems and elevations 



• It is a remarkable fact that the state 

 of Minnesota, although possessing no 

 great elevation above sea-level, gives 



rise to three of the great drainage sys- 

 tems of the North American continent. 

 Within its borders arise the Mississippi 

 River system, draining about 45,000 sq. 

 mi. of the area of the state; the St. 

 Lawrence system, arising in the north- 

 east and draining approximately 8500 

 sq. mi.; the Red River of the North 

 system, arising in the northwest and 

 draining 15,000 sq. mi. The remaining 

 area of the state is drained by four other 

 rivers which reach the three main 

 systems beyond the borders of the state. 

 Approximately 4730 sq. mi. of the south- 

 western and south-central parts are 

 drained by the Rock, the Des Moines, 

 and Cedar Rivers into the Mississippi; 

 and 10,300 sq. mi. of the northeastern 

 part by the Rainy River into the Hudson 

 Bay outlet. 



Relative elevations of different parts of 

 the state 



The lowest part of the state is the 

 land bordering on Lake Superior whose 

 elevation is 602 ft. Where the Missis- 

 sippi River leaves the state it has an 

 elevation of 620 ft. and the lowlands 

 bordering the main stream and its 

 tributaries in this region rise only a few 

 feet above that level. The flat land 

 adjoining the Red River of the North 

 where it enters Manitoba is approxi- 

 mately 770 ft. The highest elevation in 

 the state is attained in the Mesabi Range 

 north of Lake Superior which rises 2200 

 ft. above sea level. It is thus seen that 

 the lowest and the highest elevations 

 are in close proximity to each other. 



2. Geographic and local plant and animal 

 communities 



Minnesota occupies a strategic posi- 

 tion in a biological sense since diagonally 

 across it from northwest to southeast 

 runs the dividing line between the 

 coniferous forest type (Canadian Zone 

 of the Boreal Region) on the one hand 

 and the grassland and deciduous forest 

 (Transition Zone of the Austral Region), 

 on the other. The northeastern part of 

 the state is occupied by the Coniferous 

 Forest Formation which originally ex- 



