180 



channel and west of the St. Joseph River. The Lake Shore and Michigan 

 Southern Raih-oad passes along its eastern and the Grand Rapids and 

 Indiana road along its western edge. It is crossed by two wagon roads, 

 the Lima and the Goshen. Both basins are oblong, Spy Run Lake basin 

 being about four-sevenths of a mile long and two-sevenths of a mile 

 broad, Poinsett Lake basin being about one mile long and one-half of a 

 mile broad. 



The topography in general is smooth and level, with gentle swells 

 here and there, characteristic of lake bottoms. The region is drained 

 by Spy Run Creek and its tributary, the Poinsett. Numerous artificial 

 channels are led into these streams which make the drainage more perfect. 

 Where these channels do not occur, swamps are found as indicated on the 

 accompanying map. 



The origin of Poinsett and Spy Run lakes dates from interglacial 

 times. These two lakes belonged to a large class of lakes which once 

 diversified the surface of parts of the glaciated portion of the State, but 

 which now liave become extinct; irregular basins with ricli soil and 

 level bottoms remain to tell the story of their former existence. A num- 

 ber of these lakes were formed by glacial dams and may be divided 

 into two classes: those produced by the irregular deposits of moranic 

 material and those caused by the ice itself during the period of its con- 

 tinuance. It is quite probable that both of these causes united to form 

 the two lakes under consideration. As the Erie ice-lobe withdrew to the 

 northeast irregular deposits of glacial debris were left in its wake, form- 

 ing knolls and basins; these basins were in the course of time filled by 

 subsequent rains. The streams entering these basins may liave been 

 dammed by the ice front, when it occupied the position indicated bj^ the 

 lines a b on the accompanying map. The basins are enclosed at most 

 places by rather steep banks, varying in height from ten to thirty or 

 more feet. Between the basins and north of tlie stream the bank is 

 low and gentle, running back for some two or three liundred yards. 

 Indications of a shore line maj^ be seen about half-way up this gentle 

 slope, indicating a union of the two lakes. 



The length of time during which these lakes existed may be inferred 

 fi'om the depth of the silt which accumulated over their bottoms. The 

 accumulation of this silt has made favorable the growing of crops. Man 

 has taken advantage of these conditions and where it is not too swampy 

 is cultivating the soil. This is only one instance where the former 



