12 MICHIGAN ACADEMY OF SCIENCE. 



164 miles, forming about two-fifths of the fc^tate. Tlie greatest length of 

 the southern portion from north to south is 277 miles and its extreme 

 width is 25!) miles. The total area is .jS,915 square miles, with a coast 

 of over 1,G00 miles. 



The general elevation of the Upper Peninsula is 400 to 1,100 feet above 

 Lake Superior, and that of the Lower Peninsula is 400 to 600 feet above 

 the level of Lakes Michigan and Huron. 



The two parts of the State present a striking contrast in many respects. 

 The Upper Peninsula may be divided into two sections east and west of a 

 line drawn through Marquette which present very marked surface and 

 geological characteristics. The eastern portion slopes northward from its 

 southern border to a watershed and thence falls rapidly to the shores of 

 Lake Superior. This plateau contains many lakes and marshes, also fine 

 forests of pine intermixed with groves of hardwood. 



The western part is rugged and hilly, some of the hills rising 1,000 to 

 1,200 feet. In' the extreme northwest are ranges which form the cupper 

 region; the central range extends from Keweenaw Point across to the 

 Wisconsin line;, on either side are the Porcupine mountains and the 

 copper range proper. 



South and east of the copper range lies the iron range of Marquette and 

 Iron counties. The eastern portion of this peninsula is underlaid with 

 stratified rocks belonging to the Silurian period, while the western part is 

 occupied by the copper bearing rocks and those of the Huronian period. 

 Glacial drift covers deeply a large portion of both the eastern and western 

 sections. 



The Lower Peninsula is generally level or rolling, sloping up in its 

 northern portion to a central ridge or watershed which extends nearly 

 northeast and southwest, the highest part of which, in Otsego county, is 

 1,100 feet above the lake level. 



The shores along the west side of this peninsula are generally bold 

 bluffs which are constantly wearing away, while on the Huron shore they 

 are low and extending by additions of earth cast up by the waves. 



The rivers are small but their number is great, and these, with the 5,000 

 lakes scattered along the watersheds of the State abundantly water all 

 parts of it. 



Dr. C, Kominger, a former State Geologist, writes of the geology of the 

 Lower Peninsula as follows : "It forms the center-point of an oceanic bay 

 which seems to have existed without any important alteration in its 

 limits, from the beginning of the Silurian period to the end of the Carbon- 

 iferous time. We find within the space supposed to have been the bay an 

 uninterrupted series of marine deposits, following each other in the great- 

 est regularity of superposition, wliich represent all the known formations 

 deposited on this continent from the Silurian period on to the coal forma- 

 tion." The entire surface of the peninsula is covered deeply with glacial 

 drift, consisting of sand, gravels and clays variously intermixed. 



The topographical outlines of the Lower Peninsula are due to the joint 

 action of moving ice and fiowing water during and following the glacial 

 period. 



Beginning in Presque Isle county the lateral moraine of the Huron 

 glacier passes southwest near the line between Monnnorency and Alpena 

 counties, thence south by west through Oscoda, Roscommon and Clare, 

 meeting in Mecosta county, the east lateral moraine of Lake Michigan. 

 These join and pass in a southwest direction through Kent, Bari-y, Kala- 



