306 The American Geologist. November, 1894 
lateral direction remaining open to them. Now these are ex- 
actly the conditions existing here. The circular form of the 
watershed skirting the southwestern boundary of the district 
made it impossible for the waters to escape in any other di- 
rection than that taken by the rivers mentioned. 
The second family of rivers originating in connection with 
this glacial lobe was the Saginaw system. This consists of 
the Cass, Flint, Shiawassee and Tittabawassee rivers, which 
unite into a single stream some fifteen or twenty miles above 
the head of Saginaw bay, and not more than six or eight feet 
above its level. To make out their origin in detail would re- 
quire further careful investigation, but some conclusions or 
inferences may be safely drawn. These streams, as a system, 
flow in the direction of glacial retreat, that is, down the val- 
ley. It may, therefore, be inferred that they did not originate 
in the escape of glacial waters. The courses of the Cass and 
Tittabawassee are, however, a little abnormal. The former 
rises to the southeast of Saginaw ba}^, while the latter has its 
source far to the northwest. Instead of flowing directly down 
the slope to the bay, both of these streams take a course at an 
angle with the inclination of the surface and meet at Saginaw 
City, together forming a semicircle about the head of the 
bay. Small streams rising near them flow direct to the bay. 
The natural inference is that their peculiar courses are due 
to a, line of morainal embankments formed about the circular 
front of the glacier. 
It seems to me hardly probable that the great Erie-Huron 
glacial lake ever occupied this valley, or that it ever had an 
outlet through the pass to Grand river, as some have inferred. 
Such a body of water, remaining for a considerable time, 
would have so leveled and modified its bottom that the 
streams would not, after its disappearance, have taken the 
abnormal course above described. It is more likely that the 
Saginaw valley was at that time still blocked with ice. A 
smaller lake may have existed in front of the Saginaw lobe. 
One more important stream, not related in origin to those 
just described, remains to be mentioned. The Muskegon rises 
in the north central part of the peninsula and flows directly 
southwest to lake Michigan, draining an area 125 miles long, 
with an average width of only about 25 miles. The form of 
