GLACIAL LAKE LUNDY AND TKANSITION TO LAKE ALGONQUIN. 403 



The beaches in these townships have not been traced to continuous connection with the 

 identified beaches either to the south or west, so, although it seems certain .that the upper mem- 

 bers of the series belong to the Grassmere and the lower ones to the Lundy, there is no means 

 at present of distinguishing between the two groups. A number of light beach ridges and 

 several low lake cliffs with stony or bowldery flats in front of them were seen along the railroad 

 between Bad Axe and Port Austin. 



Between Bad Axe and Elkton the writer found a series of beaches closely resembling those 

 at the north hue of Sanilac County. Most of those seen, however, belong to the Grassmere, 

 for several members of the Lundy (Elkton) are farther west between Elkton and Bayport. 



Southwestward from Grassmere the writer followed two of the stronger Grassmere beaches 

 through Canboro into Tuscola County, 2 or 3 miles west of Gagetown. Two or three of the 

 upper members of the Lundy group were also seen at intervals southwest of Elkton, passing 

 Wolfton and Creel City. 



Tuscola County. — In Tuscola County the principal ridges of the Giassmere and Lundy 

 beaches were followed from Elmwood and Columbia townships southwestward about to the 

 highway which connects Vassar and Richville. Between Fairgrove, Watrousville, and Vassar 

 on the east, and Reese and Richville on the west, the beaches were studied in some detail. The 

 tendency to double ridges, which is so clearly shown by all the beaches on the road between 

 Reese and Watrousville, may be due in part to splitting, but the area covered in detail was not 

 large enough to determine the relations conclusively. The courses of the several beach ridges 

 in Tuscola County are shown in part but not fully on Davis's map of the surface geology of 

 the county. 1 



Saginaw Bay district. — South of Cass River the Grassmere and Lundy beaches pass out 

 upon the sandy floor of the Saginaw Valley and presumably lie on the gentle slope in their usual 

 relation to the higher beaches. Fragmentary gravelly ridges are well defined in certain places, 

 as in Maple Grove and Chesaning townships in southern Saginaw County, and probably belong 

 to the Grassmere and Lundy beaches. 



In Midland County there are some fragmentary ridges, but they are nearly all composed of 

 fine sand and their present forms are wind made, not wave made. The altitudes indicate that 

 the Grassmere beach enters the southern edge of Gladwin Comity barely if at all, and that the 

 Lundy does not enter it. Both turn back toward the southeast through eastern Midland 

 County to get across the Port Huron morainic system. Thence they run northward through 

 northwestern Bay County and through central and eastern Arenac County to the vicinity of 

 Au Sable River in eastern Iosco County. 



Through the entire sweep of the Saginaw Valley from Cass River to Tittabawassee River 

 in northern Midland County and thence to northern Bay County the levels of the Grassmere 

 and Lundy beaches lie on a flat clay plain, considerable areas of which are covered with fine 

 wind-blown sand. The beaches appear to have been composed of sand and have been so 

 extensively modified by wind action that almost no true beach forms remain. Where the 

 sand does not form dunes it is generally without definite expression. 



Neither the Grassmere nor the Lundy has been surely identified in this sandy region. 

 Certain wind-blown sandy ridges appear to correspond to them in a general way, but they 

 are not true beaches in their present forms. In Saginaw, Midland, Bay, and Arenac counties 

 some of the wind-blown ridges bear a slight resemblance to true beach ridges and have been 

 so described and mapped by W. F. Cooper, 2 but are shown by their details to have been shaped 

 by the winds. Their steeper slopes generally face eastward, less often northward or south- 

 ward, but so far as known never westward. The best types have almost invariably hummocky 



1 Davis, C A., Geology of Tuscola County, Mich.: Ann. Rept. Michigan Geol. Survey, 1908. The old beaches are discussed in brief general 

 terms only. The map is mainly a soil map and shows the beaches by two different symbols, which cover also other forms of surface deposit 

 which produce similar soils. The Algonquin and Nipissing beaches near the present shore of Saginaw Bay are well represented, but the mapping 

 of the older, fainter beaches at the higher levels is incomplete. 



2 Cooper describes these forms in considerable detail in his report on Bay County: Ann. Rept. Michigan Geol. Survey for 1905, pp. 343-348; 

 map opposite p. 337. Also, Pleistocene beaches of Saginaw County: Tenth Ann. Rept. Mich. Acad. Sci., 190S, pp. 90-98. Most of the lower ridges 

 here considered are of the same wind-blown sand type. Only a few are of gravel, but their composition is not stated. 



