J^E VIEWS 315 



tion of several of these outlets being noted. The last of these, the 

 Ubly channel, was the most important. The position of this channel 

 is now marked by the north branch of Cass River, a small stream flow- 

 ing in a wide valley filled with valley gravels. At Tyre, a branch was 

 received from the southeast. The relation of a great ice dam and the 

 outlet of the waters is here admirably shown. The evidence of 

 reversed drainage in the case of Black River is unmistakable. Previ- 

 ous to the opening of the Ubly channel when the ice-front was on the 

 south side of the north branch of Cass River the outlet which Taylor 

 calls the Cumber spillway was close along its edge. This position is 

 now marked by a long narrow swamp extending from the valley of the 

 Freiburger channel north of Cumber, parallel with the North Branch, 

 southwest across the South Branch of Cass River and on toward 

 Deford. In this swamp is the famous "stone wall " consisting of a 

 low embankment of earth and bowlders extending for a considerable 

 distance parallel with the edge of the swamp. Locally it is regarded 

 as the work of pre-historic man. The "wall" is about eighteen inches 

 high and was until recently obscured by vegetable mold. It was 

 exposed by fires in clearing the swamp. Mr. Taylor refers to its 

 resemblance to ice beaches but regards the explanation as unsatisfac- 

 tory. We spent some time in this vicinity and from a study of the 

 surroundings were convinced that the ice-beach theory is an adequate 

 and the only adequate explanation of the phenomena. It is of interest 

 as constituting the only instance known to us of a bowlder wall formed 

 by ice-push in a lake now wholly extinct. 



Our own observations on the beach lines of Sanilac county shows 

 a marked northward elevation corresponding to previous observations 

 in the lake region, the result probably of resilience following the 

 withdrawal of the ice and to which was evidently due the reversal of 

 the Black River drainage. This river now flows south and then east 

 into the Saint Clair River at Port Huron, An indication of reversed 

 drainage is seen in the direction of the branches of Black River as, 

 for example, that of Elk Creek which rises in the southwest part of 

 Sanilac county and flows northeast to its junction with Black River 

 which here flows nearly due south. 



While Mr. Taylor has carefully described all the glacial features 

 observed by him, and also by G. K. Gilbert who accompanied him on 

 a part of the trip, he has described no eskers. A well-marked exam- 

 ple occurs about ten miles northeast of Marlette. It consists of a well- 



