98 
EIGHTH REPORT. 
RAISED BEACHES OF EASTERN WISCONSIN. 
JAMBS W. GOLDTHWAIT. 
(Abstract.*) 
A detailed study of the abandoned shore lines of eastern Wisconsin, 
carried on in the summer of 1905 for the Wisconsin Geological and 
Natural History Survey, makes it possible not only to identify the 
beaches and terraces of successive stages of Lakes Chicago, Algonquin, 
and Nipissing, but to reconstruct the extinct water planes with con¬ 
siderable accuracy. 
Conspicuous step-like terraces on Washington island and the Door 
county peninsula mark three important stages of Lake Algonquin, and 
a twenty-foot water plane, believed to be the plane of the “Nipissing” 
shore. These shore lines were traced southward along the western 
side of Lake Michigan (and less easily along the east and west sides 
of Green Bay) ; and the profile of the whole series was measured in more 
than fifty localities, by means of the spirit or “wye” level. Assembling 
all of this data, it is found that the water planes of Lake Algonquin 
stand in warped attitudes, the direction of steepest inclination being 
about N. 15° E. Each plane rises more steeply as it extends north¬ 
ward, and the higher planes slant more steeply than the lower. 
From ninety-five feet above Lake Michigan at Washington island, the 
highest Algonquin beach declines southward at an ever decreasing rate, 
until it seems to become horizontal at twenty-six feet near Two Rivers. 
South: of that point it has been lost by more recent erosion, but seems 
to be correlated with the “Toleston” beach at Evanston, Illinois, which 
is twenty-four feet above the lake on the campus at Northwestern Uni¬ 
versity. 
The Nipissing shore line, everywhere a prominent feature, declines 
almost imperceptibly from an altitude of twenty to twenty-two feet at 
Washington island to fourteen feet at Centerville (near Manitowoc), be¬ 
coming horizontal at that height, and thus encircling the southern end 
of Lake Michigan. In southeastern Wisconsin and northeastern Illinois 
(north of Waukegan) it has commonly cut back beyond the earlier 
Algonquin shore line. Stream terraces, however, and a few scraps of 
Algonquin shore terraces seem to fix the Algonquin plane at the twenty- 
four-foot level. 
The Toleston-Algonquin shore line, horizontal at twenty-four feet, and 
the Nipissing shore line, horizontal at fourteen feet, in the southern 
part of the Michigan basin, correspond to the horizontal twenty-five-foot 
Algonquin beaches and the fourteen (?) foot Nipissing shore line in the 
southern part of the Huron basin. South of the vicinity of Manitowoc, 
there seems to have been no tilting since the beginning of Lake Algon¬ 
quin. 
This correlation of shore lines involves the use of the Chicago outlet 
as one of the outlets for Lake Algonquin at its highest stage. 
_ Evanston, Ills. 
* k The full paper will be published by the Wisconsin Geological Survey. 
