MOKAINIC SYSTEMS AT HEADS OF LAKE MICHIGAN AND SAGINAW BASINS. 215 



morainic system, have led to some changes in the interpretation of the relations of the Val- 

 paraiso system to the Kalamazoo. 



The present discussion is confined to the portion of the Valparaiso morainic system in 

 Indiana and Michigan, there being no apparent necessity for revising the discussion of the 

 Illinois portion in Monograph XXXVIII. The term "system" is used because the moraine 

 consists in places of two or more constituent ridges. As these ridges interlock at short intervals 

 they scarcely admit of separate discussion and scarcely merit individual names. 



COURSE AND DISTRIBUTION. 



The Valparaiso morainic system occupies and constitutes the high divide at the head of 

 Lake Michigan, which separates the St. Lawrence from the Mississippi drainage. Its inner 

 border is only 5 to 15 miles from the shore of the lake. Its width, including the small till plains 

 between its constituent ridges, ranges from 5 to 20 miles, and its general width is 7 or 8 nides. 

 It is one of the strongest morainic systems of the Lake Michigan ice lobe. The glacial maps 

 (Pis. VI and VII, in pocket) show its variations in breadth and complexity, and it is here neces- 

 sary to mention only a few detads of its distribution. 



In the vicinity of the State line of Illinois and Indiana there are at least three ridges in the 

 system with well-defined crests, but they are so lapped upon one another that no intermorainic 

 spaces occur. In passing eastward to the vicinity of Valparaiso the outer ridge dies out or 

 becomes submerged in the great gravel plain south of the Valparaiso system. The middle and 

 inner ridges are less distinct from Valparaiso eastward than toward the west, and in one place 

 they merge in a single great ridge about 5 nodes in width. They are blended or closely asso- 

 ciated in Michigan as far northeast as St. Joseph Kiver. East of St. Joseph River they form 

 two prominent moraines separated by a narrow till plain, but farther east, near the line of 

 Berrien and Van Buren counties, they coalesce into a single great belt which runs northeastward 

 across Van Buren County to the Kalamazoo Valley in southern Allegan County. Outside of 

 this great belt are the Kendall moraine and the weak ridges in eastern Van Buren and north- 

 western Kalamazoo counties (see p. 183) that seem to connect the Valparaiso with the Kalamazoo 

 system. North of the Kalamazoo Valley two prominent moraines appear and continue sepa- 

 rate to the southwestern part of Kent County, where the outer merges with the outer ridge of 

 the Charlotte system of the Saginaw lobe; the inner, however, extends nearly to the outer 

 ridge of the Lake Border morainic system. In western Kent and eastern Ottawa counties 

 the association with the outer part of the Lake Border morainic system is so close that some 

 difficulty is found in drawing a continuous line of separation; this, however, may follow a narrow 

 depression that runs southwestward from Grand River to Jamestown and thence southward 

 along Bear Creek to Rabbit River. North of Grand River the Valparaiso system probably 

 includes a strong moraine that lies immediately west of Grand Rapids and extends northeast- 

 ward into the bend of Rapid River near Rockford, where it connects with the correlative 

 moraine of the Saginaw lobe. It may also include the strong moraine in northwestern Kent 

 and southeastern Newaygo counties that correlates with the inner part of the Charlotte system, 

 and may also include the west part of the interlobate tract in Mecosta and Osceola counties, 

 though this, with the moraines bordering it on the west, may possibly be within the limits of 

 the Lake Border system. 



TOPOGRAPHY. 



ALTITUDE. 



Most of the inner border of the Valparaiso morainic system is between 75 and 100 feet 

 above the level of Lake Michigan, or 655 to 680 feet above sea level, and has but little range 

 in altitude. From it the surface rises at least 100 feet and in places 200 feet or more to the 

 main crest of the morainic system. In Indiana the altitude of the crest ranges from about 750 

 feet in Lake County to nearly 900 feet in Laporte County, and in Michigan from 750 to 800 feet 

 near St. Joseph River and northward across Van Buren County. The outlying Kendall moraine 

 (p. 183) reaches an altitude of about 900 feet in the northeast township of Van Buren County. 



