OTISCO VALLEY EXTINCTION OF LAKE WAEREN 53 



shoreline phenomena of the liigh-level waters, which, on account of the 

 steepness of the valley walls and the small drainage area, will probably 

 be weak. The lake we may call the glacial Otisco. The lower part of 

 the valley contains, however, heavy deltas, and is related to the great 

 channels and other critical phenomena connected with the extinction of 

 lake Warren. 



Near the village of Amber, at the foot of the lake on the east side, are 

 conspicuous terraces. The elevation of these is given on the Skaneateles 

 topographic sheet as between 940 and 960 feet. Upon the faces of the 

 deltas is a notching, 50 or 60 feet lower. The Amber deltas were built 

 by rivers which drained the glacial waters of the Onondago valley, 

 lying east. The lake in which the deltas were deposited, which we will 

 call the Marietta lake, seems to have had its level determined by some 

 winding channels in shale rock two miles due east of Skaneateles village, 

 with elevation on the topographic sheet of 940 feet (see figure 1). This 

 outlet carried the waters over to the Skaneateles valley by a fall of only 

 about 20 to 30 feet, from whence it escaped still westward by the Mandana 

 channel (see page 52) to the ^^'arren waters, by a fall of about 30 or 40 

 feet. Other deltas formed in the Marietta lake occur two miles south of 

 Marcellus,on the east side of the valley. The Marietta lake was succeeded 

 in the Otisco valley by the Warren waters at full height, which produced 

 tbe lower notching on the. Amber deltas. 



EXTINCTION OF LAKE WARREN: HYFER-IBOQUOIS WATERS 



Two miles south of Marcellus village a huge delta lies on the west side 

 of the valley at the mouth of a great channel cut in the Hamilton shales 

 (see plate 5). The topographic sheet gives the height of the delta ter- 

 races as 860 down to 800 feet. The delta is the debris derived from the 

 excavation of the gorge and dropped by the powerful river in the slowly 

 falling waters of the Otisco valley. The gorge heads four miles north- 

 west of Marcellus and a mile west of Sheppards Settlement on lime, 

 stone, with an elevation at the intake, as given by Dr Gilbert, of 812 

 feet.* Here at the head of the eroded " gulf " (the only local name) the 

 drift and shale are removed down to the hard limestone rock over con- 

 siderable area (see plate 4). It is evident that an enormous volume of 

 water escaped at this point. This was the water of lake Warren, which 



*The channels and deltas at the foot of the Otlseo valley were first brought to the writer's notice 

 by Dr Gilbert in 1896. These and the other large channels farther eastward, described later in this 

 paper, were studied by Dr Gilbert and briefly noted in his paper in the Bulletin, vol. 8, p. 285. 

 Through the kindness of Dr Gilbert and the courtesy of the United States Geological Survey sev- 

 eral of Dr Gilbert's photographs of the channels are used in illusti-ation of this article. These 

 include the views in plates 4-7 and figure 2 of plate 8. 



