GEOLOGY: NORTH SHORE. 



J. Edmund Woodman. 



PLUM ISLAND DUNES. 



Eoute. — (1) From North Union station by Eastern division, Boston 

 and Maine railroad, to Newburyport ; electrics eastward from station to 

 near Merrimac square: liorse cars from Meriiraac square to Plum Island, 

 nortli end. Single fare $1.00. (2) By same rail route to Ipswich; walk 

 to boat ; take boat for Plum island, south end. 



Fine dune action, constructive and destructive, can be seen 

 here — in operation if tliere be a wind. The formation of eolian 

 ripples, structure of dune-sections, encroachment of wind-blown 

 sand westward, swamping up of protected shallow-water areas 

 between the mainland and the off-shore bar forming the island, 

 protection by beach grass, and filling of lagoons by eolian sand, 

 are among the phenomena visible. Marine action itself is not so 

 varied in its effects as elsewhere. 



BEACH BLUFF AND MARBLEHEAD NECK. 



lioKte. — By rail, Eastern division Boston and Maine road, Marblehead 

 branch, from North Union station, tickets for Beach Bluff; fare $.30. 



By wheel, to Lynn by way of Broadway, Chelsea; thence along line 

 of Swarapscott electrics to within one block of Beach Bluff station. Turn 

 to right in either case, to water front. 



Marine action is powerful all along this part of the coast. A 

 pretty continuous bench can lie followed north to the wall beach 

 and in places elsewhere. Between Marblehead Neck and the 

 mainland to the south is a magnificent boulder beach, on which all 

 the phenomena characteristic of such a form occur. The rocks 

 composing it represent all the phases to be found between Mar- 

 blehead and Swampscott. A great variety of erosion forms occur 



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