34 NEW YORK STATE MUSEUM 



an elevation of about 800 feet. The enormous volumes of coarse 

 detritus carried by the Altona river was first thrown into Lake 

 \'ermont southeast of West Beekmantown, at and south of the ham- 

 let known as Beartown, where an area of several square miles is 

 buried under coarse delta stuff which might be mistaken for moraine. 

 The courageous farmers have tried to clear the land by building 

 huge cobblestone fences around small fields, which fields are yet 

 masses of cobble. 



As the ice sheet weakened and the Altona river was lowered on 

 the land slope Lake Vermont was also falling and the stream 

 detritus was dropped at about 700 feet altitude two miles north of 

 West Beekmantown and three miles southwest of West Chazy. 

 The closing phase of the drainage was into Lake A^ermont at about 

 600 feet, producing heavy deposits at Cobblestone hill, northwest of 

 West Chazy. , 



The areas of stripped and eroded rock are the most striking and 

 peculiar features of the region. These are the Stafford's rocks 

 between Covey gulf and Cannon Corners, with altitude 900-7<^S 

 feet; Blackman's rocks, southeast of Cannon Corners, about 800- 

 700 feet ; and the Altona bare rocks, 900-620 feet. The channeling 

 erosion by the Altona river has produced a striking series of north 

 and south valleys south of the bare rocks. The correlation of the 

 bare rock areas with the Covey gulf was correctly predicated by 

 Wood worth. 



While the ice front was holding the river flow along the lower 

 edge of the Altona rocks the ice weakened on the north slope of 

 Covey hill so that Lake Iroquois found escape around the promon- 

 tory and was lowered to the level of the Altona river, toward 700 

 feet. This stream control, along the east side of Pine ridge, estab- 

 lished for a time a lake in succession to Iroquois, which we propose 

 to call Lake Einmons (after Ebenezer Emmons whose district in the 

 first geologic survey of the State covered this territory, and who 

 first drew attention to Covey gulf). For a relatively brief period 

 Lake Emmons occupied the Ontario basin, producing some con- 

 spicuous delta sand plains. It left a few strong beaches, near 

 Altona, at Cannon Corners and at the extreme northwest corner of 

 the jMooers quadrangle, the altitudes ranging from 740 down to 

 680 feet. The strength of these bars, formed in a narrow lake, is 

 surprising and is not satisfactorily explained, unless we can attribute 

 the efifcctivc wave action to the calving of small icebergs or the 

 dumping of the ice front in shallow water. 



This sequence of events connected with the Covey gulf river 

 ex]3lains why no high cataract clifif was formed at the east end of 

 the gulf. All the flow exce])t possibly the very latest was held up to 

 high level and forced south by the obstructing ice front. Even the 

 greatest drop could be only 250 feet, or to the level of Lake Emmons. 

 A swamp filling at tlic Emmons level occupies the old valley below 

 the gulf. Probably the outflow of Iroquois was diverted from the 

 gulf to the north side of the hill while the ice front was holding the 



