380 STEVENSON 



On the west side of the valley, a striated surface of Lower 

 Pentamerus, corresponding to that on the east side, is reached 

 at less than half a mile north from the bridge ; while the till is 

 shown at about the same distance south, on the Middleburgh 

 road, where it makes a very cold soil. On this side an angular 

 bowlder of much sheared gneiss, measuring 4 by 6 by 5 feet, 

 was seen, at 370 feet (by barometer) above the river, on the 

 Caudi Galli slope and near it another of gneiss, about half as 

 large. Water-worn fragments of gneiss are scattered over the 

 surface everywhere from the river to the hill tops, while angular 

 fragments of transported rocks seern to be rare. 



The distribution of the till and the direction of the striae seem 

 to show that the valley, as it now appears, has practically the 

 same shape as before the ice invasion. The several benches of 

 harder rock must have existed in the earlier time as now on the 

 east side, where they are separated by the long gentle slopes of 

 softer rocks ; for, far back from the river, the Upper Pentamerus 

 bench is scratched, while lower down and nearly one third of a 

 mile nearer the river we have the Lower Pentamerus beautifully 

 striated, while lower yet we have the benches of Tentaculite and 

 Coralline well polished and covered with till. The cutting done 

 by the ice must have been comparatively small ; bowlders of 

 Pentamerus and Tentaculite were not seen up the valley above 

 the horizons of those rocks. This weakness in cutting is shown 

 also by the peculiar form of the benches in Mix and O'Reilly's 

 quarry. 



Note. — Since this paper was read, Messrs. Clarke and Schuchert have published 

 their scheme of the New York Series, in which are revived some of the older 

 names, for which certain terms used in this paper will become synonyms. 

 ''Hudson" is synonymous with "Lorraine"; "Waterlime" is the " Rondout 

 Waterlime " of Clarke and Schuchert; "Tentaculite" is synonymous with 

 " Manlius " Vanuxem ; " Lower Pentamerus " and " Delthyris " will be replaced 

 by the newer terms " Coeymans " and " New Scotland " of Clarke and Schuchert. 



November 22, 1900. J. J. S. 



New York University, New York City, October, 1899. 



