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MN 4. Lake Agassiz Peatlands Natural Area. Acreage: 22,000. <^ 



Location: Koochiching County; International Falls 1:250,000 Quadrangle; 30 Z 



miles S of International Falls. [J] 



O 

 Description: Registered Natural Landmark. Lake Agassiz Peatlands Natural H 



Area represents an outstanding example of the extensive peatlands which occu- 



py a major part of the bed of ancient glacial Lake Agassiz. It illustrates the 



process of peat accumulation in the 1 1 .000 or so years since Lake Agassiz 



receded. 



Myrtle Lake Bog in the southern portion of the area presents an unusual 

 phenomenon. Ecological studies, peat borings and topographical surveys show 

 that as the bog surface around Myrtle Lake was built upward, the water table 

 also raised; thus elevating the surface by at least 12 feet, so that Myrtle Lake 

 continues to exist, contrary to the usual successional process of Lake filling. 



A splendid example of a raised bog occupies some 5000 acres in the northern 

 portion of the area. This bog type is characterized by an elevated peat dome 

 which supports a cover of heath shrubs, sphagnum moss and stunted black 

 spruce. Topographically oriented' communities of spruce radiate downslope 

 from the summit of the peat dome. 



Fine examples of string bogs aggregating about 3500 acres occupy the 

 drainageways leading to the two principal outlets of the peatland. These string 

 bogs are characterized by elongated boggy ridges covered with shrubs, and 

 tamarack, alternating with treeless, sedge covered hollows. The ridges and hol- 

 lows lie across the slope at right angles to water movement. 



References: Hiinski man, M. L. 1970. Landscape evolution, peatland types and 

 the environment in the Lake Agassiz Peatlands Natural Area, Minnesota. Ecol. 

 Monogr. 40:235-261. 



Encroachments: Administered by the State Division of Forestry as a natural 

 area to be preserved without disturb., ze. 



Ownership: State of Minnesota. 



Data source: NPS. 



Map on following page 



