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NEW YORK STATE MUSEUM 



all the characters of the so called Flat rock or spillway so well 

 shown about Altona. On the west the old stream bed springs as 

 out of the air across the swamp near the crest of the col. Nothing 

 else than the front of the Wisconsin ice sheet, pressed against and 

 around the northern slope of Covey hill and the northern flanks 

 of the Adirondacks to the westward, could have held up to this ele- 

 vation the waters which discharged eastward through " the Gulf " 

 to the lower levels of the Champlain valley. The present investi- 

 gation has not determined the precise origin of these waters — 

 whether they came from the ice itself, from the large streams 

 which, descending the northern slopes of the Adirondacks, dis- 

 charged against the ice front ; or whether any part of the water 

 passed along the front of the ice to this point from the northeast- 

 ern extension of some stage of Lake Iroquois, a large fresh-water 

 lake retained over the site of present Lake Ontario by the western 

 extension of the same ice dam which is here invoked for the anom- 

 alous drainage feature of " the Gulf." 



The facts at " the Gulf " warrant the conclusion that, at the 

 time the ice sheet stood along the boundary so as to hold the drain- 

 age up to this col, there was a free run off for the water from at 

 least the upper lakelet at an elevation as great as 830 feet above 

 the present sea level. This, as will be shown later, precludes the 

 idea of a glacial lake existing above this level at this particular 

 time over the Champlain valley. The same remark holds true for 

 the bottom of the gorge at the lower lakelet : while the water still 

 flowed through this gorge at the latest stage a glacial lake could 

 hardly have existed to the south and east at a higher level than 

 the 645 foot level. [See p. 41 for further bearing of facts a/t 

 Covey hill on water levels] 



"The Gulf" is a witness also against the presence of the sea 

 within the range of its elevation and shows that the deltas and 

 shore lines within these levels southward along the slopes of the 

 Adirondacks are not of marine origin. 



Small rock exposures 



The small rock exposures shown on the map — care has been 

 taken to show all that were observed — fall into two groups, arti- 

 ficial and natural exposures. The artificial exposures are in this 



