20 The American Geologist. July, i8£9 
The Alcana-Hamburg Dam. The next halt of the ice-front 
in Michigan was at the Alcona moraine, and this seems to 
correlate with Leverett's Hamburg moraine in western New 
York. The ice-dam in the Huron basin at this time was some- 
thing o.ver 200 miles long and at its apex stood in water nearly 
500 feet deep. The Hamburg dam was probably somewhat 
longer and its point stood in about 450 feet of water. The 
island of the Ontario highlands still remained, but had been 
slightly enlarged by the drawing back of the ice and by a fall 
of more than too feet in the level of the lake waters along its 
southern shore. 
Tlie Hagcnvillc-Aldcn Dam. At its next halt the ice-dam 
stood at the Hagenville moraine in Alichigan and at the Alden 
moraine in New York. In the Huron basin the dam was per 
haps a trifle longer than in the preceding position and its apex 
stood in water about 50 feet deeper. The Alden dam was 
probably not more than 150 miles long and its forward part 
stood in water not more than 300 feet deep. The Alden dam. 
is believed by the present writer to have stood along the north 
side of the lower course of Grand river in Ontario, turning 
north and northeast around the western end of lake Ontario. 
Observations tending to that conclusion were made at three 
points on the supposed course of the moraine by the writer in 
1897, but owing to its being waterlaid its recognition is not cer- 
tain without further and more connected tracing. 
The Lockport Dam. The next halt of the ice-front in New 
York was at the Lockport moraine. No correlative for this 
moraine has yet been identified with certainty in the Huron 
basin. The Lockport moraine is probably, but not certainly, 
identified with a moraine on the opposite side of lake Ontario 
running northeast from Scarboro Heights a few miles east of 
Toronto. If this surmise is correct the dam could hardly have 
been less than 100 miles long and its apex must have stood in 
water nearly 1,000 feet deep. 
The Albion Dam. At its next rest in New York the ice- 
front stood at the Albion moraine. Nothing corresponding to 
this has been reported from Michigan or Ontario. The depth 
of water was about the same as for the Lockport, but on its 
south side the dam extended much farther east, probably to 
the hills south of Syracuse. At this stage of retreat a lobe of 
