CHANNELS EAST OF LIMESTONE VALLEY 65 



vation at the rapids of 840+ feet. The cataract and cain^on head are 

 comparable to those of the Jamesville gorge, being of lesser depth and 

 without a lakelet. Ths bottom of the amphitheater and canyon is a 

 smooth meadow. The can3^on leads northeast one mile and joins the 

 east-arid-west Pools Brook hollow, which has an elevation somewhat 

 over 520 feet, and opens near Mycenae upon the plain at 460 to 480 feet 

 elevation. The western end of this hollow, toward Fayetteville, is ap- 

 jDarently obstructed with knolly drift. The col is about one mile east 

 of Fa3^etteville, with an elevation of about 560 feet. 



Northeast of Fayetteville, about one mile, is the head of another chan- 

 nel, with elevation by the map of 540 feet, which leads quickly down to 

 the low plain 400 to 420 feet. Round and Green lakes, which'lie in the 

 cliannel course, the latter with 418 feet elevation, have been examined by 

 Mr Gilbert, Avho pronounces them sinks due to underground drainage. 



These easternmost channels may have been deserted, due to earlier 

 removal of the ice barrier from this localit}^, while the Railroad channel 

 and perhaps the High Bridge channel were still effective. 



It will be observed that the Mycenae channel terminates at a level 

 above that of even the later Iroquois.* Dr Gilbert has noticed this and 

 suggested a baselevel of water in the eastern Ontario basin due to an ice- 

 dam in the Mohawk valley. The suggestion is here offered that perhaps 

 a lobe of the ice body Ij'ing in the Oneida lake depression pressed against 

 the high ground northeast of Oneida village, and so held the pre-Iroquois 

 waters of this localitj^ higher than the Rome col. If this lie so, there 

 should be broad waterwa3^s between Oneida and Rome at an elevation 

 over 500 feet. 



On the north side of these lower eastern channels the drift is de- 

 cidedly morainal, much more so than is indicated b}^ the topographic 

 sheets. This is especially the case with the two channels east of Fa3'ette- 

 ville and with the High Bridge channel. 



Hypiiir-Iroquois Channels near Syracuse 



The fall of the glacial waters in the Ontario basin from the Warren 

 level (880+ feet) to the primitive Iroquois level (440 — feet) was by a 

 series of leaps, as the retreat of the ice-front uncovered successively 

 lower channels toward the Mohawk valley. The district from 15 miles 

 southwest of Syracuse to 12 miles east was the critical region, apparently 



* It should be understood that the primitive Iroquois had a lower level on its southern border 

 than the later lake, on account of the lower altitude of the Rome outlet, and that during the long 

 life of the Iroquois its waters transgressed this shore and buried many features under the great 

 silt plain. 



