1921] EDWARDS, GLACIAL LAKE LAPHAM. 97 



most western is the earliest in point of time, and was followed by 

 the eastern ridges in succession. 



If we attempt to picture the condition of the drainage of this 

 vicinity, at the time when the ice sheet stood along the line of the 

 middle moraine, it will be readily seen that the continuation of the 

 ice front across the valley of the Menominee river would naturally 

 cause a diversion of that stream to some other outlet than the one 

 it now pursues. This, of course, is equally true of all other east- 

 ward flowing streams that were crossed in the same manner by 

 the ice. Those streams to which attention has been given in the 

 present work, include, besides the Menominee, the Kinnickinnic 

 river. Oak creek at South Milwaukee, and the Root river, just west- 

 ward of the City of Racine. All of these, it has been found, were 

 similarly bkjcked by the extension of ice across their valleys and 

 consequently their waters, also, must have been diverted into other 

 channels. Their present drainage eastward into Lake Michigan, is 

 probably due to the fact that they were able to discover a low point 

 in the moraine after the melting of the ice, and, by subsequent 

 erosion, were successful in carving out the valleys which they now 

 occupy. 



As soon as this condition of affairs was appreciated, an exami- 

 nation of the topographic maps was undertaken in order to ascer- 

 tain the approximate extent of the lake which would be formed in 

 the Menominee River valley. It was found that this body of water 

 would, in all probability, be united with the waters standing in 

 the valleys of the Kinnickinnic river, of Oak creek and of the Root 

 river, forming one continuous lake along the front of the glacier. 

 This body of water, which it is now proposed to name Lake Lap- 

 ham, probably had its outlet through the south Ijranch of the Root 

 river, across the very low divide which now separates that stream 

 from the Des Plaines, and flowed into the Des Plaines river, from 

 there to the Illinois, and so on to the Mississippi. 



The altitude of this outlet of Lake Lapham is such that the 

 waters of the lake would stand at approximately 720 ft. above 

 sea level. 



Further work in the western edge of the city has shown some 

 of the dei)osits which were formed in this lake. These are especial- 

 ly noticeable in the district known as West Milwaukee, and in 

 the bluffs on the banks of the ]\Ienominee river near the West 



