Along the entire shore line we again find that trees grow only 

 on the abrupt, sheltered slopes, or on areas protected by such 

 slopes, and that the flatter unprotected shores are treeless. The 

 forest map thus again becomes in fact a topographic map. 



The flatter beaches are mostly sandy, or muddy northward, 

 while opposite the higher banks, marked by the forest fringe, the 

 beaches are bowldery. Outlying or connected pools and swamps 

 are quite frequent along all the lower shores. Bowldery reefs 

 are usually found extending into the lake from the more abrupt 

 points along the shore line. These often form an anchorage for 

 interesting water plants, such as Potamogeton, etc. 



Eastward from this lake the uplands rise to form the water- 

 shed between the Des Moines river of the Mississippi drainage 

 and the Little Sioux river of the Missouri drainage. Southeast- 

 ward there are several kettleholes, of which the largest and most 

 interesting is Prairie lake, which drains into Lower Gar lake. 

 It is a shallow lake densely crowded with water plants, especially 

 at the northeast end. Its banks rise to a height of 10 or 15 feet, 

 and, where abrupt, shelter small groves. A wooded ridge almost 

 cuts off a swamp on the northwestern side. The level of Prairie 

 lake is much higher than that of East Okoboji lake (about 80 

 feet?), and the ridge to the northwest, between the two lakes, 

 near the church, is over 40 feet above the level of Prairie lake. 



The Gar lakes form an interesting chain extending southward 

 from East Okoboji lake. The Middle lake is the deepest, reach- 

 ing a depth of from 10 to 20 feet. The Lower lake scarcely 

 reaches a depth of 6 feet. As before, the more abrupt banks, 

 with bowldery beaches, are marked by a forest fringe, while the 

 flatter shores, often swampy, sometimes sandy, are treeless. The 

 Upper Gar lake, and that part of Lower Gar which receives the 

 water from the outlet of Prairie lake, contain the richest aquatic 

 vegetation in the Gar lake group. 



West Okohoji lake is by far the finest body of water in Iowa, 

 and it, together with its immediate vicinity, furnishes; to both 

 botanist and zoologist unusual opportunities for field-work. Its 

 irregular outline and much greater depth bring about a variety 

 of conditions unequaled in any other lake of the state. It con- 

 nects with East Okoboji lake by a narrow strait, crossed by a 

 railway and a wagon bridge, and the shallow portions of both 

 lakes adjacent thereto offer a fine field for work. From this 



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