PECULIAR ESKERS AND ESKER LAKES I 2 J 



area of at least twenty-five acres is studded with mounds and 

 kettles, averaging about one each to the acre. One of these 

 mounds has been excavated, and is shown to be made up of a 

 uniform mixture of two thirds coarse gravel and one third clay. 

 The clay forms a tough cement which holds up the material in 

 a perpendicular face. The mixture might be called a clay con- 

 glomerate. A few large boulders occur in this tract. It is con- 

 tinued on the east by an isolated gravel mound rising to 65 feet 

 above lake level. 



The system of ridges forms an irregular parallelogram which 

 nearly encloses the basin of High Lake. The northern part of 

 the basin is occupied by a tamarack swamp. The area of open 

 water is about half a square mile, mostly from 10 to 35 feet 

 deep. It is deepest toward the south and west shores. There 

 are no inlets except ditches from a few insignificant marshes, 

 and in summer evaporation equals or exceeds supply. The 

 overflow is by a small ditch to Bear Lake. The basins of the 

 two lakes are really continuous, being only partially separated 

 by the sand and boulder ridge. That their waters were once 

 united is shown by a well-developed beach which borders the 

 ridge and fills the gap between it and the till-spur. 



This peculiar grouping of diverse and strongly marked 

 features forms a puzzle difficult of solution. The east-west gravel 

 ridge presents the characters of a subglacial esker, yet its 

 height, steepness of slope, short extent and isolation are unusal. 

 The presence of the great kettle hole piercing its center from top 

 to bottom is not the least remarkable feature and contributes to 

 the general impression of unnaturalness. The north-south ridges 

 are sufficiently esker-like, but the western one is continuous, 

 without notable change in form or direction, with the till ridge. 

 The latter is an esker in form but its material is that of a sub- 

 marginal moraine. Its northeastward extension presents some 

 of the characters of a pitted sand plain or esker-delta, but it is 

 complicated by the presence of the clay conglomerate and the 

 kame-like sand and gravel knobs. The general indications of 

 the surrounding country are that the Saginaw ice here moved 



