Great Ice- Dams. — Taylor. . 25 
slight westward declivity, except in the last three miles, where 
the descent is more rapid over a sill of limestone. 
The boundaries of this first stage of lake Maumee are fully 
known, provided we suppose a continuous ice-wall along the 
Defiance moraine to have constituted a water-tight barrier on 
that side. The lake was shaped somewhat like a barbed arrow- 
head with the point at Fort Wayne and the barbs at Findlay 
and Adrian. It was about 40 miles wide east and west between 
Defiance and New Haven and 50 miles north and south 
through Defiance, while from the point to the barbs was about 
7S miles each. All the boundaries of this first stage of lake 
Maumee are well shown on Mr. Gilbert's map referred to 
above. The Maumee beach is nearly level throughout and is 
on the average about 220 feet above lake Erie. 
Mr. Leverett describes the beach in the following words: 
"The Van Wert ridge so far as I have examined it consists 
in the main of a deposit of sandy gravel, though for consider- 
able distances it presents only a wave-cut bench free from 
gravels. It is not a strong beach, its usual hight being 2-5 
feet and its breadth but 10-12 rods. Occasionally, however, 
opposite where streams tributary to the lake had their de- 
bouchure, it is much larger, standing 12-15 feet above the 
plains on either side of it and having a breadth of 20-40 rods 
or even more."* 
Lake Maumee. (Second or two-outlet stage.) As the ice- 
front retreated from the Defiance moraine, it uncovered new- 
ground upon which the water advanced as fast as the ice re* 
ceded. Theoretically, the waves must have begun immediately 
to make a new beach, which would appear as a faint extension 
of the Maumee beach, because made at the same level. North- 
east from Adrian a long, tapering bay was gradually opened 
between the ice and the land just uncovered and this bay ex- 
tended far up into Michigan to Imlay City west of Port Huron, 
where a new outlet was opened. The old channel of this outlet 
extends from near Imlay City north and northwest to a point 
a few miles beyond the village of North Branch and then turns 
to the southwest, passing down the valley of Flint river. This 
channel is quite narrow as compared with the other outlets 
of these waters, being only about one-third of a mile wide. It 
*Am. Jour. Sci., April, 1892, pp. 286-287. 
