PLEISTOCENE GEOLOGY OF MOOERS QUADRANGLE 



23 



This quotation is given here for the reason that it appears to 

 be the first recognition of an important class of abandoned gorges 

 found in New York State excavated across northward extending 

 promontories of rock and lying so far above the present drainage 

 of the country that no existing stream under the geographic con- 

 ditions of the day could have performed the work. Dr Gilbert 

 appears to have been the next geologist to examine this gulf and 

 the first to understand it : it was he who first called my attention 

 to its existence. His notes on the place give the depth of the 

 ravine as 160 feet; top of cliff above lower lake, 805 feet above 

 sea level; the lower lake, 645 feet above sea level; upper lake, 

 830 feet above sea level; bluff above upper lake, 870 feet above 

 sea level; swamp at summit, 875 feet above sea level; margin of 

 channel opposite swamp on north side, 900 feet; water level of 

 torrent at swamp inferred to have been between 900 and 910 feet. 

 These are aneroid readings compared with the U. S. G. S. 

 measurement of the elevation of Covey hill top, which is given 

 as 1030 feet. No accurate measurements have yet been made of 

 the depth of the upper and lower lakelets. The international 

 boundary line crosses the lower lakelet as shown in plate 11. 

 The upper lakelet lies wholly within Canada. 1 



The small lakelet at the foot of the cliff at the head of the gorge 

 is clearly a waterfall pool, analogous to Green lake near Syracuse. 

 The lower lakelet at the eastern end of the gorge, where the valley 

 widens out into a depression of more ancient date, appears to be 

 due to the choking of the valley at the eastern end of the lakelet 

 as if a powerful stream reaching this point was checked and 

 forced to drop its load. At the lower margin of the upper lakelet 

 there is a heap of angular blocks of the Potsdam sandstone show- 

 ing the action of the turbulent currents once active within the 

 pool. 



The rock on either side of the brink of the gorge and particu- 

 larly along the southern side is stripped bare of drift and displays 



x " The Gulf" is most easily reached from the south by driving from 

 Mooers to Armstrong's Bush in the northwest corner of the quadrangle, 

 thence to Covey Hill postoffice and westward over the top of the hill 

 to Mr Donnelly's or farther on to Mr Sutten's place, from the latter of 

 which a private road leads to the head of the gorge and the bare rock 

 of the channel above the abandoned waterfall. 



