254 The Parallel Drift-Hills of Western Neiu York. 



jiosing rock in Wayne County, or in ^yestern Cayuga, its course 

 is obstructed in several places by bars of boulders remaining 

 from the drift which it has cut away. Examples may be seen 

 between Lyons and C!lyde, and at tlie latter village ; another, 

 further east, will be alluded to presently. Along tliis river val- 

 ley are a few of the hills previously mentioned as exceptional, 

 having steep southern declivities^, evidently due, in a measure, 

 to the erosive action of the river. One section of this river val- 

 ley deserves our particular attention — that stretching from the 

 foot of Cayuga Lake to the hills in the southern part of Wayne 

 County. It comprises more than forty thousand acres of marsh 

 lands, through which the Seneca pursues a northerly course by 

 an almost imperceptible current. Indeed, so slight is the fall, 

 that in times of flood the great volume of water brought down 

 by the Clyde flows south as well as north, and has even dis- 

 colored Cayuga Lake as far south as Springport. At such 

 times, many of the smaller valleys are filled with back-water, 

 particularly that in which lies Crusoe Lake ; and Cayuga virtu- 

 ally extends to within a dozen miles of Ontario. That it did so 

 extend in reality, at no very distant day, becomes evident 

 when we examine the marsh. This is undei'laid throughout its 

 whole extent by several feet of shell marl, composed of the shells 

 of existing species of Unio, Planorhis, Pliysa, Limnma, etc. 



Furthermore, upon the borders of the marsh, at Monteznma 

 and in the southern part of the town of Savannah, are found 

 salt springs rising from beneath the marl in a manner jDrecisely 

 similar to those of Salina. As is well-known, these latter rise 

 from beneath a layer of shell marl underlying Onondaga Lake, 

 and overlying from four to six hundred feet of gravel, which 

 fills an ancient excavation, and serves as a reservoir for the 

 brine. 



Beds of sand, showing wave-action, also fringe the marsh in 

 numerous localities. 



The region for some distance north of Seneca Lake is also 

 generally low and level, and is drained by slow and sluggish 

 streams. Swamps are numerous and extensive, and not unfre- 

 quently enclose shallow lakes and ponds. Skirting this low- 

 lying region are also beds and hills of sand, shoAving wave-action 



