44 On the occurrence of Freshwater Shells 



Not only have marine shells and this fresh water species been 

 found at Green's Creek, but also the remains of two seals, three 

 kinds offish, leaves, wood and nuts of land plants, three or more 

 species of marine algae and specimens of Asteracanthion polaris 

 Mull, the most abundant starfish now inhabiting the Lower St* 

 Lawrence, and future researches at this localitv will no doubt 

 add many more fresh water, as well as marine species, to our Post 

 Pliocene fauna. 



Terraces aroukd Lake Ontario. 



On the south side of Lake Ontario a remarkable ridsre* com- 

 posed of loose materials, extends from Sodus in Wayne County wes- 

 ward to Lewiston on the Niagara River, a distance of 100 miles 

 and a continuation of the same ridge has been traced to the head 

 of the lake. The general contour of this " Lake Ridge," as it is 

 called, is parallel to the present shore of the lake, its extreme varia- 

 tions being three miles at its least and eight at its greatest distance 

 from the shore. A carriage road runs along its summit, the gene- 

 ral elevation of which is so uniform, that when the road is toler- 

 ably straight, a traveller can be seen as far as the eye can reach. 

 A remarkable feature of this ancient boundary of the lake is that 

 it declines more or less on the inland, as well as the lake side, 

 thus constituting a true ridge, which damming the surface water, 

 forms marshes on the upper side. This fact can be no objection 

 to the supposition of its marking a former boundary of the lake, 

 for we find similar ridges now forming along low exposed shores. 

 The rarity of shells in it, is perhaps as a circumstance in favour o^ 

 the supposition of its being of fresh water, and not marine origin, 

 as shells are very scarce along the open shores of the great lakes, 

 and one might search a long time in similar ridges now forming 

 without finding any. 



The elevation of the summit of the ridge above Lake Ontario 

 opposite Middleport is 185 feet, opposite Albion and Brockport it 

 is 188 feet. The distance comprised within these three observa- 

 tions is thirty miles, in which the elevation of the ridge varies 

 only three feet; in Wayne County it is estimated at 200 feet. 

 Fragments of wood, shells, &c., are found embedded in it; the 

 shells were not collected by Mr. Hall himself but he has no doubt 



* The facts here given in regard to the " Lake Ridge " are derived 

 from Hall's Geology of New York, Part IV. 



