446 THE ILLINOIS GLACIAL LOBE. 



have been developed prior to the formation of that beach, and probably 

 has the same age as that noted near Evanston, Illinois. 



POSSIBLE SECOND EMERGENCE. 



As indicated above, features near Holland, Michigan, apparently call 

 for an interval of emergence there between the formation of beaches which 

 stand second and third in the series of that region. Immediately south and 

 east of Holland a beach is built up from the level of the plain on which 

 Holland stands, which is 30 to 40 feet above Lake Michigan, to an elevation 

 60 to 65 feet above the lake. It consists of sandy gravel, becoming in 

 places nearly clear sand. In connection with this deposit there is a sandy 

 gravel which extends 2 miles or more up the Black River Valley, and has 

 the appearance of being a delta accumulation formed by a larger stream 

 than the present river. A broad abandoned channel nearly a mile in width 

 leads from Grand River just below Grand Rapids southwestward to the 

 Black River Valley at Holland, which has opened a broad passage through 

 this delta, or rather a double channel, with an island-like remnant of the 

 old delta south of Zeeland. The amount of erosion would be great if it 

 had extended only to the level of the marsh; but judging from the depth of 

 the channel of Black River from Holland westward to Lake Michigan, 

 which, as shown above, reaches a level 30 feet below the lake, the marsh 

 has been greatly filled during the formation of a lower beach which crosses 

 Black River at Holland. The filling can not well be less than 50 feet. 

 This depth of excavation not only increases the work done but indicates 

 that there was sufficient emergence above the level of the present shore of 

 Lake Michigan to cause stream channeling to extend 30 feet or more below 

 lake level. The relation of the lower beach to the head of the lake-like 

 expansion of Black River is discussed in connection with the Third or 

 Tolleston beach. 



Deep channeling on the lower course of other eastern tributaries of 

 Lake Michigan, above noted, appears to have occurred contemporaneously 

 with that of Black River. What relation this channeling may have to the 

 Algonquin and Nipissing lake stages is yet to be determined. During each 

 of these lake stages the water in the south part of the Lake Michigan Basin 

 is thought by those who have studied their beaches to have been below the 

 present level of Lake Michigan. But it is also thought that in the northern 



