AN OUTLINE 



OF THE 



GEOLOGY OF MOUNT DESERT. 



By WILLIAM MORRIS DAVIS. 



'T^HE mountain range of Mount Desert includes the 

 ■*• highest of a number of mountainous hills that rise 

 over the rolling lowland of southern Maine. The lowland 

 has been slightly inclined to the south, so that a part of 

 its original area is depressed under the sea, to make the 

 platform of the Gulf of Maine ; while its northern exten- 

 sion slowly ascends inland until it deserves the name of 

 a plateau in the northern part of the State. The tilted 

 lowland is roughened by the excavation of numerous 

 valleys ; and since these were formed the coastal region 

 has been slightly lowered, carrying the sliore line farther 

 inland than before, changing many a valley into a long 

 arm of the sea, and isolating many a hill top as an out- 

 lying island. Associated with this later change of level, 

 and during a time of colder climate, there was an invasion 

 of the region from the north by a sheet of ice, such as 

 that which still maintains possession of Greenland, The" 

 slow but rough-shod march of this cold conqueror stripped 

 the loose soil from the land, wore down the sharper 

 ledges of the hills, deepened many of the valleys, and 

 dragged along the rubbish thus gained farther and farther 

 southward. When the invader was driven away by the 

 return of a milder climate, the rubbish or "drift" was 

 irregularly disposed over the uneven lowlands, thereby 



