The outlying region to the east, north and west of the lake is 

 rolling prairie, with higher knobs visible in the northwest. 



East OJtohoji lake is a narrow, irregular shallow body of 

 water. Thronghont its northern two-thirds the depth scarcely 

 reaches 6 feet, and during dry seasons becomes much less. In 

 1896, and again in 1902, it was almost impossible to row a boat 

 in any portion of this part of the lake on account of the shallow- 

 ness of the water and the abundance of vegetation (see Plate 

 VII, figs. 2 and 3). The southwestern portion of the lake reaches 

 a depth of about 25 feet. The northern end of the lake is bor- 

 dered by a sandy beach. Southward both shores are formed by 

 higher banks and bluffs more or less wooded, those on the west 

 side and beloAv the town of Spirit Lake varying from 10 to 55 

 feet in height (see Plate VII, fig. 3). Where the lake turns 

 westward abruptly the shores become flatter and the surface rises 

 gradually to the north to an elevation of over 75 feet. That 

 part bordering the west side of the lake in section 10 is cut by 

 ravines, and tongues of prairie, similar to that shown in Plate I, 

 fig. 3, follow the tops of the ridges into the wooded area. Near 

 the railway station Okoboji the banks are again higher, and more 

 or less forested. The east side of the lake is also bordered more 

 or less by uplands. The east banks of the northern lobe of this 

 lake vary from 10 to 20 feet in height, and there is a distinct 

 border belt of forest. From the drawbridge at Spirit lake south- 

 eastward to section 11 the low bluffs are irregular, variable in 

 height, and in places recede from the lake. In sections 11, 14 and 

 15 the bordering upland is more massive, the bluffs or slopes fol- 

 low the lake more closely, and the whole area is heavily wooded, 

 forming the largest forest in all the territory discussed in this 

 paper. 



West of this forest and extending to Stony Point, the shores 

 are a^ain lower, the slopes from the uplands more gradual, and 

 treeless. A group of mounds extends westward from Stony 

 Point, and here again the more abrupt, sheltered slopes and val- 

 leys are forested. Beyond these mounds another low, treeless 

 section borders the lake. Twin Mounds, which will be further 

 discussed, present both prairie and forested slopes (see Plate V, 

 fig. 1 ) . Thence to the south end of the lake the banks are quite 

 abrupt, and in places a second line of uplands approaches close 

 to the lake. 



7 



