General physiography: bedrock control of the coastal platform . The 

 geology of the Maine coast, characterized by deeply indented embayments , 

 straight, high, rocky cliffs, broad mud flats, and numerous coastal islands, 

 is unique in the Eastern United States. Maine's complex shoreline 

 physiography is determined by the structured nature of the bedrock. The 

 bedrock determines the general shape of the shoreline and the shallow complex 

 bathymetry of the coastal waters. The Maine coast from Cape Elizabeth to 

 Eastport can be seen as three segments on the basis of bedrock geology (figure 

 2-16). Regions 1, 2, and 3 are included in the area characterized by indented 

 embayments. Regions 4, 5, and part of region 6 (east to Machias Bay) are 

 included in the island bay complex. The eastern area of region 6 is 

 characterized by a cliff shoreline. 



Bedrock units are cut transversely by fault and fracture systems of varying 

 orientations and ages. The major fracture system that cuts coastal bedrock 

 units (generally from southwest to northeast) developed during the late 

 Devonian-Triassic time frame (180 to 350 million years ago). Fracture systems 

 in the bedrock exert major control over groundwater flow. A record of 

 geological events and their correlation with plant and animal evolution is 

 given in figure 2-17. 



Eastern 

 Cliff 

 Shoreline 



Island - Bay 

 Complex 



Stratified Rocks 



O m M DEVONIAN ■ MISSISSIPPI 

 0,. EARLY DEVONIAN 

 SILURIAN 



ORDOVICIAN 



Plutonic Rocks 



Q PERMIAN TO CRETACEOUS VOLCANICS 

 flA granitic 



{£•£> gabbfoic 



MID- TO LATE DEVONIAN 



Figure 2-16. Bedrock geology of coastal Maine (Doyle 1967) 



2-37 



10-80 



