I04 The A)iic}icaii Geologist. . Februarj, isi'fs 
of the region. It seems that a further investigation in the 
field is necessary to determine whether the highest beach at 
Duluth, 1,137 fs^t above sea level, is associated with the gla- 
cial passes thus far described, and whether the Boulevard 
beach at Duluth may not be regarded as the highest beach of 
lake Duluth. 
Along the Duluth and Iron Range railroad the highest 
margin of the lake is found between five and six miles north, 
of Two Harbors, and at an altitude of about i,iod feet above 
sea level. The lake shore is not clearly defined on account 
of the even slope of the glacial drift, but it does not appear to 
extend over 50c) feet above lake Superior. At mount Jose- 
phine the highest beach has an altitude of 1,209 f^^^ above sea 
level. North of Silver motmtain the Port Arthur, Duluth 
and Western railroad crosses the highest beach, about thirty- 
eight and one-half miles west of Port Arthur, at an altitvide of 
about 1,230 feet above sea level. 
Deltas. Delta deposits are prominently developed on the 
Knife, Encampment, Gooseberry, Beaver, Baptism and Tem- 
perance rivers. The most extensive development of these 
deltas was contemporaneous with the stages of lake Duluth. 
Lake Ominii. Before the ice haci receded beyond 
mount Josephine it retained a lake of about 40 square miles in 
area lying in the upper valley of the present Pigeon river. 
The lake bed has an altitude -of 1,255 ^o i'36o feet above the 
sea. Its lowest point is thus about 50 feet higher than the 
upper stage of lake Duluth. The chief deposit consists of 
stratified clay, exposed along the Pigeon river and its tribu- 
taries. Beaches have as yet not been identified. The west- 
ern shores of this lake were formed by high rock ridges. The 
ice barrier during the largest extent of the lake stood in the 
vicinity of the western end of the Grand Portage trail. The 
outlet, which has not been definitely located, was most proba- 
bly toward the southeast, and closely connected with the ice 
barrier, which, upon receding, continually uncovered lower 
ground. This lake in part occupied a portion of the area 
previously occupied by the northern ice lobe. When the ice 
receded from the vicinity of Grand Portage, lake Omimi dis- 
appeared. The name Omimi is taken from the Chippewa 
name for Pigfeon river. 
