The Valley of Grand River, Michigan. — Mudge, -^ i 
must have bssn speedily formed in the loose drift below, al- 
lowing the water to rush down tin- sloping surface of the 
more unyielding rock at a violent fate. 
An examination of the river valley below the great bend 
shows that tile stream in its formative period encountered at 
this point an entirely new set of conditions. The valley above 
this point exhibits only insignificant glacial Hood terraces, or 
they are entirely absent. Below, however, they are a promi- 
nent feature, the valley becoming broad, flat-bottomed, and 
capacious. It consists of the meandering stream channel, the 
present flood terrace or flats, and a glacial flood terrace some 
feet higher, on which are built the towns of Muir, Ionia. Sar- 
anac, Lowell, and Grand Rapids. The distance between the 
drift blutt's at Ionia is not less than a mile, contrasting greatly 
with the narrow upper valley. The change from the one con- 
dition to the other takes place very abruptly at the great bend. 
It is evident that a great glacial flood once rushed down this 
valley: and it is also plain that this torrent came not from the 
south through the upper Grand valley, but from the east, 
through the valley now occupied by the Maple river, which 
enters the Grand at the great bend. It issued from the west- 
ern front of the Saginaw valley glacial lobe; and if we cor- 
rectly interpret the valley evidences, it was one of the most 
important glacial outlets in this part of the country. The 
upper Grand river was but a branch or feeder of the main 
stream. The latter continued to occupy the great depression 
which crosses the state at this place until the glacial front 
had receded over the low watershed into the Saginaw valle}*. 
It then dwindled in size until it is now represented by the 
rather inferior stream known as the Maple river, a mere 
branch of the more important Grand river. 
Having determined with reasonable certainty the origin of 
the Grand river and its tributary, the Maple, it is interesting 
to inquire what became of their combined waters as they pro- 
ceeded on their western course. Lake Michigan and the 
adjacent territory, as well as lake Huron with the Saginaw 
valley, and also lake Erie, were occupied by a great glacial 
lobe, a portion of the continental glacier. During the retreat 
of this part of tin- ice-sheet it became divided into three lobes, 
namely, an eastern one. moving outward westerly from the 
