LAKE MICHIGAN DRAINAGE BASIN. 541 



received after the stream enters the Valparaiso system, and it drains only 

 a narrow strip scarcely 6 miles in average width. As above noted ; it enters 

 the St. Joseph River within a mile of the lake, and the two drainage systems 

 are, therefore, nearly distinct. 



BLACK RIVER. 



Three nearly distinct drainage systems, known as North, Middle, and 

 South Black rivers, drain a district in southwestern Allegan and northwest- 

 ern Van Buren counties lying west of the Valparaiso morainic system. 

 They unite before passing through Covert Ridge, and the united stream 

 enters the lake at South Haven. The north branch leads westward from 

 the "Pine Plains" to Covert Ridge, and there is deflected southward. Mid- 

 dle branch takes a nearly direct westward course from the "Pine Plains" to 

 its junction with the north branch. The south branch is deflected north- 

 ward in its lower course along the east border of Covert Ridge. 



KALAMAZOO RIVER. 



This stream, with a drainage area nearly as large as the St. Joseph 

 River, has been deflected at several points by morainic ridges formed by 

 the Saginaw lobe, but the lower course through the Valparaiso morainic 

 system and districts to the west is somewhat direct, This lower course 

 was opened after the ice sheet withdrew from the Valparaiso system. The 

 discharge during the occupancy of this morainic system was apparently 

 southward into the St. Joseph River. The peculiar complications of its 

 history can only be appreciated after a description of the moraines of the 

 Saginaw lobe. This will appear in a separate report now in preparation. 



The Kalamazoo River receives only one important tributary in the 

 district west from the Valparaiso morainic system. This tributary — Rapid 

 River — drains a narrow belt in the northern part of Allegan County, 

 extending from the east border of the Valparaiso system westward through 

 the inner members of that system and across the "Pine Plains" to the 

 outer border of Covert Ridge, where it unites with the Kalamazoo River 

 (see PI. XV). 



