193 Wisconsin Academy of Sciences, Arts and Letters. 



ing 80 feet or more, while other portions are but 30 feet above Lake Mich- 

 igan. The depth of sand at the powder works near Miller, is 32 feet. 

 Beneath the sand is gravel and sand in which are shells of mollusks called 

 snail shells by the well-digger, who reported them. The elevation of the 

 surface is probably not more than 50 feet above Lake Michigan. 



Gravel has been encountered near the bottom of wells along the ridge 

 in several instances; the writer has no means of computing accurately 

 the elevation above Lake Michigan, but it is certainly not more than 20 

 feet. The Lower beach in Michigan occurs at iatervals only. It consists 

 of dunes and low sandy ridges lying back of the dunes of the present 

 beach, which form a bold front along much of the Michigan shore. They 

 are usually separated from these higher dunes by marshy belts, but some- 

 times lie immediately back of them. Their height seldom exceeds 40 feet, 

 while the dunes along the shore are in some cases 125 feet or more in 

 height. 



The most southerly development of these older ridges in Michigan is 

 found on the east side of the Michigan Central railroad in New Buffalo 

 township, where they extend for more than a mile along the railroad. 

 North from here no ridges of this epoch were noticed south of the clay 

 banks, in Tp. 7 S. , R. XXIV, but north from there to the vicinity of St. 

 Joseph, dunes were noted at frequent intervals lying east of the belt along 

 the shore. A similar distribution of two series of dunes was noted west of 

 Carrot, in Van Buren county. Further north this Lower beach was not 

 thus identified. Occasionally gravel deposits are exposed along the lake 

 shore, capping the till at elevations of 10 — 20 feet, which may represent this 

 epoch, but quite as frequently these deposits, as has been already noted, 

 rise to heights corresponding with the elevation of the Middle beach (30 — 35 

 feet above Lake Michigan). The main development of the raised beaches, 

 not only of this epoch, but of all ef)ochs, is found in Illinois and Indiana, 

 for it is only around the head of tlie lake that the land has gained more 

 than it has lost since the epoch of the first (Uijper) beach. 



