POET HURON MORAINIC SYSTEM AND PKOBABLE CORRELATIVES. 299 



CUMBER, HAY CREEK, ARGYLE, AND BAD AXE SPILLWAYS. 



The Cumber, Hay Creek, Argyle, and Bad Axe spillways appear to have been uncovered in 

 successive order from south to north during the retreat of the ice front, and all of them are prob- 

 ably somewhat older than the Ubly channel, for they were made when the ice was beginning its 

 retreat to a position farther north than that marked by the Port Huron system. The Ubly 

 channel was made only when the ice front had readvanced to the position of the main Port 

 Huron moraine. The retreat and readvance of the ice front at this time will be more fully 

 discussed later. (See pp. 362-3S5.) 



Cumber spillway. — The Cumber spillway, which lies close south of the Ubly outlet, is in its 

 lower three-fourths almost as well developed as the Ubly. In its headward part it is not maturely 

 developed. It opens westward out of Black River swamp south of Tyre through two or three 

 head branches whose floors are of stony till and were not much deepened although considerabl}- 

 widened by the flow of the lake waters. The Cumber spillway is particularly well developed in 

 western Austin and southwestern Greenleaf townships, where the stony till ridge between the 

 Ubly channel on the north and the Cumber on the south is hardly half a mile wide and seems 

 clearly a remnant left from the scouring of the two channels. Rock ledges are exposed in it 

 just east of Holbrook. The lower part of this channel in southwestern Greenleaf is as finely 

 developed as the Ubly channel; in it is located the "stone wall" 1 — a small rampart ridge of 

 bowlders produced apparently by the onshore shoving of ice in a shallow bay or lake — described 

 by Gordon and others. 



The Cumber channel extends southwestward to the middle of Novesta Township, Tuscola 

 County, and may connect with the bowldery belt in Novesta and Wells townships and farther 

 on with the East Dayton channel. This correlation, however, seems very doubtful in view of 

 the differential uplift of the land. The flat ground upon which it emerges has now an altitude 

 between 740 and 745 feet, which is about the same as that of the head of the East Dayton chan- 

 nel. Before the elevation of the land the ground in Novesta Township was about 15 feet lower, 

 which would leave little or no declivity toward the southwest and little chance for scour along 

 the line of the bowlder belt. 



Hay Creek spillway. — Opening from the swamp east of Frieburger another smaller spillway 

 runs west to a point south of Cumber and thence southwest down Hay Creek to the middle 

 branch of Cass River. The lower part of the Hay Creek spillway was deeply cut and has a 

 swampy floor, but it is relatively narrow and its headward parts are undeveloped. 



Argyle spillways. — In Argyle Township two headward branches of Cass River join and flow 

 westward. Although they have no well-developed channel they flow in valleys which seem much 

 too large for them and which evidently served as temporary spillways. 



The south branch of Cass River follows a line of swamps which may be hi part an esker 

 trough, but which may have been a temporary spillway joining the Argyle spillway at Shabona. 

 The swamp forks in the southeast part of Lamotte Township, one branch going northwest past 

 Novesta; neither branch shows distinct scour, but both may have served as very temporary 

 spillways. 



Bad Axe spillways. — When the ice front began to recede from the Port Huron morainic 

 system it uncovered ground slightly lower than the col at the head of the Ubly channel and per- 

 mitted the formation of two winding, swampy passages that led through the mterlobate hills 

 between the Ubly channel on the south and the edge of the interlobate high ground at Bad Axe 

 and Verona Mills on the north. These channels are only 70 to 80 rods wide, but then- bowldery, 

 swampy floors show the scour of the stream that passed through them. One of them is about 4 

 miles north of Ubly and passes close to Wadsworth with an altitude of 785 to 790 feet. The 

 other somewhat wider channel lies about a mile south of Verona Mills. It seems evident that 

 these channels were occupied for a relatively short time and that they probably divided the 

 overflow with the Ubly channel. 



1 Gordon, C H., Geological report on Sanilac County: Michigan Geol. Survey, vol. 7, pt. 3, 1900, pp. 18-20. Taylor, F. B., Bull. Geol. Soc. 

 America, vol. 8, 1897, pp. 43-M. 



