THE GLACIAL PLKIOD AND ITS RLCORDS 



on either side of Keweenaw Peninsula. In places the moraines 

 of adjacent lobes were pushed together, making a jumble of 

 high hills such as the scenic Irish Hills of southeastern Michi- 

 gan and the high hills of the northern part of the Southern 

 Peninsula. These morainic hills, with their beautiful lakes 

 of ponded waters and with clear streams rushing down their 

 slopes, give to the glaciated region its varied and picturesque 

 beauty. Other parts of the country have hills carved from 

 the bed rock of the region, but the glaciated district, particu- 

 larly in Michigan, has also hills built by a plastering of rock 

 waste scraped off Canada, transported and dumped by the ice. 

 The ice in the Saginaw Bay lobe melted faster than the ice of 

 the Michigan and Huron-Erie lobes, because it was thin over 

 the rim of the Marshall (Mississippian) sandstone — one of our 

 old "rock bowls." Its retreat was rapid and marked by brief 

 halts, with the result that the moraines of that lobe are 

 grouped in a necklace arrangement of pendant festoons about 

 the bay — narrow belts of low rolling hills with broad flat 

 valleys (outwash plains) between, in contrast to the high 

 sharply-hilled moraines of the other glacial lobes. In other 

 states of the glaciated area and in the Northern Peninsula of 

 Michigan much of the bed-rock is exposed at the surface or 

 the drift is thin, but in the Southern Peninsula the burial 

 cover of glacial drift is so thick that bed-rock appears at the 

 surface in but few places. Hence secrets of mineral wealth in 

 the underlying rocks have been preserved until mechanical 

 ingenuity made it possible to drill through the thick cover 

 of drift. 



High conical gravelly hills mark the sites of water falls 

 where streams flowing in channels or tunnels high in the ice 

 fell over its edge and piled their rock debris in dumps at the 

 foot of the falls. Such hills, known as kames, standing alone 

 or in groups of several on the till plain or in the terminal 

 moraine, may be easily recognized by their form and by their 

 water-sorted contents where these are exposed in excavations. 



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