CEDAHVALE CHANNEL AND DELTA 59 



ley " lake, after the southern suburb of Syracuse. The elevations of this 

 lake and of the terraces of the Cedarvale river delta were ordered by 

 the heights of the series of outlets southeast of Syracuse, near Jamesville, 

 Avhich are described below. 



CEDARVALE CHANNEL AND DELTA 



These are the finest examples of such combined phenomena in western 

 New York. The head of the channel and upper, narrow, rock excava- 

 tion near Marcellus have alread}^ been described (see page 56 and plate 

 6, figure 1). The total length of the present channel from Marcellus to 

 South Onondaga is about nine miles, of which the low^er six is mostl}'' 

 a broad preglacial valley that the Cedarvale river filled with delta drift, 

 and subsequently reexcavated in part. The delta is of magnificent size 

 and form, even in its present fragmentary state. It is separated into 

 two great masses. The liigher and upper portion is a great plateau south 

 of Cedarvale postoffice, with area of more than one square mile. The 

 terrace which forms the head of the delta is indicated on the TuUy sheet 

 by the contour of 860 feet. Lower extensive terraces eastward are 840 

 and 820 feet elevation. The southeastern third of this great remnant is 

 a broad plain of 680 feet elevation. Evidently the broad open valley 

 west of Cedarvale must have been filled with delta drift. A conical 

 mound, over 40 feet high, of cemented gravel, stands conspicuously in 

 the open valley, one mile northwest of Cedarvale, as a witness to the 

 general filling at the sub-Warren level and subsequent erosion by the 

 Cedarvale river. A stretch of open valley about one mile wide, exca- 

 vated b}^ the later stream, separates the Cedarvale delta mass from that 

 at South Onondaga. This village i's situated on a 600 feet terrace of a 

 great island-like plateau, having a summit level of about 770 feet and 

 an extended eastern terrace of 660-670 feet.* This mass is over a square 

 mile in area. Still lower terraces stretch east and then north two and one- 

 half miles, with faces cut by stream action similar to those in the Marcellus 

 valley. These lie partly in the Onondaga Indian reservation. South of 

 the creek and south and southeast of the village of South Onondaga is a 

 broad delta plain somewhat over 640 feet elevation, with lower terraces 

 southeastward. The head of this southward delta plateau was built by 

 a southern stream pouring down the valley slope from Joshua, 500 feet 

 higher. The power of this lateral stream is exhibited in a highway ex- 

 cavation where the deposit is a mass of boulders ranging in size up to 

 two and three feet in diameter. 



♦These figures of altitude about the Onondaga valley are taken from the unpublished Tally and 

 Skaneateles sheets of the New York topographical map and may require some correction; but they 

 are sufficiently accurate to discriminate the several delta levels and correlate them with the deter- 

 mining outlets. 



IX— Bn.T,. Geot.. Soc. Am., Vol. 10, 1898 



