45 



much htrger tiiaii tlir syiiimt'trical. varyinti in liri^lit t'niiii tivc to twcnt y-tive tVct 

 al)<)ve till' lioiu'ral levol. The avcraj^v is |inil)al)ly alxnit trii tVot! Tlu' suiiili and 

 west slopes are gradual and mori' or less broken, while the nortli and ea>l slopes 

 are steep and even. Horizontally these slopes are very sinuous, resendiiing tiie 

 hanks of winding streams; iuit the I'ael that at their bases, often streteliini; lo the 

 north and east for a mile or more, are extremely level expanses freipienily cov- 

 ered with peat, forcing upon even the unoliserving the recognition of old lake 

 beds, dispels the idea of their being such. . Al the same time the winding course 

 of the ridges jjrohibits the idea of their having been thrown up by wave action 

 from the lakes. In many places these ridges are too sandy to be cultivated with 

 protit, in others the soil is good, and at a few points, to ))e mentioned later, gravel 

 has been found. They ai'e fre(|uently cut through by what apparently were 

 escapes for the water confined by them. In these cuts, which usually reach to (ir 

 near the base of the ridge, bowlders can pretty conlidently be searched for. 

 Bowlders are also occasionally found along their l)ases. 



Only in the gravel pits above referred to has the writer seen any indication 

 of stratillcation. Two of these pits are situated a mile and a (piarter west of 

 Rensselaer, near the Iro(piois River. There are three others a mile and a half 

 south of Rensselaer. Places in these show attempts at sorting by ra])id and 

 changealile currents, hut the greater ))art of the material is unsorted, and it would 

 seem that their deposition was effected almost wholly l)y direct glacial action. 



Let it be repeated that the two tyi>es often grade into each other. A ridge 

 that in places presents the most rugged aspect of the unsymmetrical, may, in the 

 course of a raile, grade into the most feeble of the symmetrical type; and at a 

 point about three miles north of Remington an unsymmetrical ridge grades into 

 a low, flat ridge covered with numerous bowlders, and evidently a moiaiui'. 



Of course, the thing of interest in connection with these ridges is the question 

 of tlieir origin. It has been cdaimed (Twelfth An. Rej). ( ieol and Nat. Hist, of 

 Ind., page 66) that they are dunes fornu-d along the northeast and east shores of 

 former lakes, and were produced by southwesterly winds. While the examination 

 of numerous cuts has not disclosed the least sign of lamination by either wind or 

 water, there seems to be no doubt that the unsymmetrical ridges are due very 

 largely to seolian action; but it does not seem that the low, flat, symmetrical 

 ridges, so frequently connected, or passing into each other and forming the rims 

 of ponds could have been produced in this way. The fact that the two types 

 grade into each other indicates a common origin at least of their basal i)ortious. 

 Also the fact that bowlders are more numerous along and near the bases of these 

 ridges, especially the symmetrical type, tlian elsewhere, together with the fact tliat 



