394 PLEISTOCENE OF INDIANA AND MICHIGAN. 



This fainter back ridge might be thought to be an Arkona ridge lower than the rest, but 

 its behavior after crossing to the north side of Mill Creek proves conclusively that it was made 

 after the building of the main moraine of the Port Huron system. It shows no tendency to 

 follow the Arkona ridges up the Black River valley. It must have been made before the great 

 barrier beach was built and in a relatively short time, for it is rather weak. 



The rugged, land-laid part of the main moraine of the Port Huron system comes down from 

 the north and terminates in a remarkably sharp point in the southeast corner of sec. 27, Clyde 

 Township. (See fig. 5, p. 366.) In all probabilit} r it formerly extended half a mile or more 

 farther south or southeast. From this point the Warren beach runs almost directly north to 

 the north line of St. Clair County. It has its usual tendency to a double form much of the way, 

 but the two ridges are set close together and in few places differ more than 8 or 10 feet in height. 



Sanilac County. — In Sanilac County the beach runs directly north to a point west of Port 

 Sanilac and then a little west of north to Huron County. Its development in this interval is 

 quite even, but its lakeward slope grows more gradual toward the north and its two ridges are 

 separated by about a mile at the north line of the county. At Charleston, 2 miles south of the 

 line, the upper ridge is one-quarter of a mile west of the village and the lower one in the village, 

 the difference in altitude being about 10 feet. Possibly the lower ridge divides again, but the 

 relations have not been fully worked out. 



Huron County. — In Huron County the two ridges of the Warren beach run north-northwest, 

 the upper passing 1 mile and the lower 2 miles east of Ruth, eastern Sigel Township. Both 

 ridges are finely formed in this interval, but are not developed in great strength except at some 

 places where streams pass through them. Their lack of strength in Sigel Township is probably 

 due to the wide shallows to the north. 



In eastern Sigel Township they turn west and run along the base of the interlobate hills 1$ 

 miles north of Verona Mills, the lower ridge being 10 or 15 feet below the upper and less than 

 half a mile north of it. Lane 1 gives many details of this beach. 



From a point a mile north of Bad Axe a low morainic ridge, separated from the interlobate 

 hills to the south by a trough a mile wide, runs eastward for 4 miles. The beaches enter this 

 trough at its east end but fade away toward Bad Axe. 



In the western edge of Bad Axe both the Warren ridges reappear in much stronger form. 

 The lower one is excavated a little west of the village for ballast by the railway. Both ridges 

 are composed of rather coarser and cleaner gravel than is common. 



From about 1J miles west of Bad Axe the beach runs southwest to Popple with the high- 

 way upon its crest most of the way. In this interval it is unusually high above the plain to the 

 northwest and from 10 to 20 feet above an extensive swamp to the east and south. In part 

 of this stretch it is a barrier bar shutting off the low ground behind it. A mile west of Popple 

 a high mo ramie knoll is heavily cut away on its northwest side at both the Wayne and Warren 

 levels, leaving a bluff 60 or 70 feet high. 



Southwestward from this point the beach runs southeast through a shallow embayment 

 for 5 or 6 miles, and again runs southwest with reduced strength past the east side of Mud Lake. 

 A mile southwest of Rescue it becomes a strongly wave-cut bench along the northwest face of a 

 narrow morainic ridge (the same apparently that runs east north of Bad Axe) and so continues 

 into Tuscola County just west of Gagetown. 



Tuscola County. — From Gagetown the beach follows the inner slope of one of the later ridges 

 of the Port Huron system southwestward to a point about 1J miles southwest of Watrousville. 

 In most of this interval of about 20 miles it is a strongly wave-cut shore line, with high lake 

 cliffs at many points and with a few short intervals of a heavily formed beach ridge of gravel. 

 West and northwest of Caro it contains large deposits of gravel. West of Watrousville it is a 

 rather indistinct beach ridge, filling short intervals between wave-cut bluffs. But it seems 

 probable that in the stretch from Rescue southwest nearly to Vassar much of the cutting of the 

 moraine was done by a large river coming from the Bad Axe spillway and flowing between 

 the ice and the moraine. 



1 Lane, A. C, Geological report on Huron County: Michigan Geol. Survey, vol. 12, pt. 2, 1900, pp. 62-73. 



