GLACIAL LAKE AEKONA. 369 



BEACH A, AEKONA (?). 



In the Black River valley there is a beach 10 to 12 feet above the first Arkona beach. It 

 is faint and fragmentary and has the washed-down appearance seen in the other Arkona beaches 

 where they have been modified by submergence south of Spring Hill. One or two small frag- 

 ments occur in the north edge of St. Clan County, but all of the better parts are in Sanilac 

 County. The best examples lie on the slopes close below the strong Whittlesey bars west of 

 Amadore, west of Croswell, and southwest and west of Applegate. 



A few small fragments of beach A lie farther south, but as a continuous ridge it begins 

 rather abruptly near the southwest corner of sec. 30, Worth Township, whence it runs 

 northeast, curving to north through the middle of sec. 19. For 6 miles the ridge is very 

 broken, and the beach seems absent in four gaps 1 to 2 miles wide. A small fragment occurs 

 at the southwest corner of sec. 7 and another 2 miles to the north and a little west. A mile 

 farther northwest a low beach ridge runs north-northeast for 2 miles through sees. 35, 26, and 24, 

 Buel Township. Then after another gap of a mile this beach reappears in stronger form and 

 runs northward along the west line of Lexington Township in sees. 18, 7, and 6. One more frag- 

 ment runs north about a mile in sees. 35 and 26, Washington Township, to about 1 \ miles west 

 of Applegate. A small gravelly patch farther north on the south line of sec. 22 may represent 

 it, but beyond this, if present, it is buried under sandy outwash. This is 20 miles north from the 

 Spring Hill road. 



It is possible that beach A is a mere local splitting from the first Arkona beach, due to 

 uplifting and tilting of the land, which affected only the region of this valley, but at present 

 no proof of this is available. 



Another possible explanation makes beach A a relative of the Whittlesey beach rather 

 than of the Arkona beaches, for if, as seems to be indicated by its character, the Whittlesey 

 beach was gradually pushed up the slope while it was being made, beach A may be the remains 

 of the Whittlesey beach at its first level. A faint ridge along the base of the Whittlesey beach 

 east of Ypsilanti suggests the same relation. The further fact that it was not found in the 

 Saginaw Valley is significant. On account of these uncertainties, it has not seemed best to 

 designate beach A as the first beach of Lake Arkona, although that may be its real relation. 



RELATION OF THE AEKONA BEACHES OP THE BLACK RIVEE BAY DISTEICT TO THE POET HURON 

 MORAINIC SYSTEM AND TO LAKE WHITTLESEY. 



The relation of the lower ridge to the two above it in sec. 30, Grant Township, shows how 

 absolutely unique is the relation of the fragment of the third beach east of the river in sec. 8 

 to the moraine. (See fig. 6.) In sec. 30 the three beach ridges he upon a gentle slope which 

 declines eastward toward Black River and the beach ridges are like steps going down the slope. 

 The ridges face eastward over lower ground and within a few rods back of each ridge the clayey 

 plain rises gradually to a higher level. Thus it is totally out of the question to think of these 

 ridges or any one of them as made by waves coming from the west. The waves came distinctly 

 from the east and could not have come from any other direction. Yet as one follows the lower 

 ridge up to sec. 8 and sees the front of the great moraine coming nearer and nearer, until at the 

 little fragment on the east side of the river the foot of the moraine actually touches the eastward 

 face of the beach ridge, and as one sees the massive bulk and height to which the moraine 

 is piled directly in front, the situation and history of tins locahty become little short of dramatic. 

 Standing on the beach and endeavoring to restore in imagination the conditions which existed 

 when that beach was made, one must imagine the entire bulk of the great moraine to be removed 

 and in its place a wide sweep of waters deepening in front of or eastward from the beach over 

 the area where the moraine now stands. 



The facts and relations here are so clear and plain that this description, drawn in the effort 



to reconstruct the conditions and events of the past, is not fanciful but portrays things as they 



really occurred. When the beach ridge was being made, the massive moraine was not there, 



nor was the great ice sheet which built the moraine. At that time the ice front must have 



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