QUATERNARY FORMATIONS — THE DRIFT. 229 



terraces further south. These rise in some cases almost vertically, to 

 a height of more than 100 feet. The distance between them and the 

 bay varies from a few rods to half a mile or more, and the interval is 

 strewn with water-worn fragments of rock and occasional slight beach 

 ridges. 



The three forms united. ISTear Green Bay (Sec. 24, T. 24, E. 21 E.) 

 there is an. inconspicuous beach ridge, formed of worn chip-stone, 

 first appearing on the bay shore and extending a few rods, when it is 

 replaced by a well defined terrace of red clay, which extends south- 

 ward nearly parallel to the shore for about two miles, when it is in 

 turn replaced by a low, flat, sandy ridge, which may be traced around 

 the extremity of the bay and northward along the western side to the 

 Menomonee and beyond. 



The intimate association of the ridges and terraces here exhibited, 

 and found less conspicuously elsewhere, leaves no doubt that they are 

 only different phases of the same formative process. 



Between the lake shore and the terrace of red clay and of rock, the 

 surface does not usually exceed fifteen feet above the lake level. The 

 sandy ridge that succeeds the terraces rises to the northward, reach- 

 ing 44 feet in Sec. 9, T. 33, E. 29 E., being the most northern point 

 at which the elevation was taken. The rocky or gravel ridge attains 

 a greater height. 



At Hedge Hog Harbor it is 40 feet. 



At Big Sister Bay 65 " 



At Eagle Harbor 53 " 



At Egg Harbor 60 " 



At Fish Creek 55 " 



The elevation becomes less again toward the southern extremity of 

 Green Bay. These elevations were all taken upon the crest of the 

 ridge. 



Secondary Beach Linen. Between this ancient beach and the pres- 

 ent one, there is frequently a second well defined ridge of lower ele- 

 vation, and occasionally a third. These are sometimes sandy and 

 sometimes composed of rock fragments, like the primary ridges. 



GENERAL MOVEMENTS. 



The movements made by the agencies which produced the foregoing 

 Quaternary formations are of an exceedingly interesting character. 

 There was first the advance of the great glacier through the deep 

 basin now occupied by Lake Michigan, and through the Green Bay 

 valley. The diagram of glacial movements, given on a previous page 



