ON THE COAST OF MAINE. 327 



ference in the character of the underlying rock which is mucli less easily riven hy the ice 

 action than the rock on the east side of the Bay. This sliore therefore wants the distinct 

 inclined plane of detritus, which we have described as occurring on the western side. 



Tlie Megobben Reach offers us a carious case of a continuous valley l^'ing in a position 

 where its formation cannot well be accounted for by the excavating character of ice action. 

 From certain indications derived from the form of the " roches moutonees" in this reach of 

 water, I was somewhat inclmed to think that a part of the great stream which poured from 

 the Penobscot Bay during the glacial period, was turned from its more southei-n course to 

 pass through this valley. From the general character of the valley, however, I am now 

 inclined to consider it as marking the jjlace of a great east and west ftiult line, which has 

 been developed b}' the ice action. Along its whole shore the drift lies in thin masses, being 

 much less developed than in the country to the west of the Penobscot. The reason for 

 tills is likely to be found in the hard nature of the rock lying to the north. Moreover, the 

 transporting power as affecting the distance whence the detritus could have been derived 

 would liave been greater in the valley region of the Penobscot than on this shore where 

 the gathei'ing together of ice streams did not occur. 



At Sedgwick there occurs a considerable indentation in the shore to the northward, 

 marking the point where the harder syenitic is replaced by a soft serpentinous rock, in 

 which the pebble-armed ice managed to make a .deeper cut. The barren hills at this point 

 and to the eastward as far as the village of Brookline, are denuded of all the small drift, 

 nothing of the glacial debris being left except the larger boulders. This stri^jping, which I 

 am compelled to refer to the action of the sea during the period of depression, extends from 

 near the water line to at least two hundred and fifty feet above the sea. Many of the 

 heaps of boulders are wedged together as if they had been strongly beaten by wave action. 

 A part of the deep waters which surround Mount Desert lie between Brookline and that 

 Island ; the small islands which dot its sm'flice have but little drift upon them, and this in 

 no way characteristic. The insular masses which lie to the southward of Megobben Reach 

 were not visited by me on account of severe weather, which rendered it difficult to pass 

 the intervening waters. So far as seen they had the same cliaracter as the rocks to the 

 eastward, there being comparatively little drift on their faces. Re2)ort has recently come 

 to me of the discovery on Deer Isle, at the height of about two hundred feet above the 

 sea, of a mass of marine shells of the same age as the beds at Portland. 



On the Island of Mount Desert the evidences of great subsidence during the glacial 

 period are few and inconspicuous. The reason for this is probaljly to be found in the fact 

 that owing to the great height of the hills the secondary glaciation was quite strong and 

 long continited, and resulted in sweeping away to the seaward the product of the erosion 

 during the principal ice time. The re-elevation of the island was ^jrobably complete, or 

 nearly so, before the ice ceased to pour from the hills into the sea. It is only close to high 

 water mark, say within twenty or thirty feet or so, that there are any distinct signs of 

 stratification in the glacial material. The evidence of the existence of extensive local 

 glaciers is very perfect. The niunerous valleys leading from the hills have all more or less 

 distinct moraine heaps along their course. The valley of Great Pond is dammed to the 

 southward by a moraine mass, having a height of about one hundred feet above the water. 

 I have mdustriously searched the flanks of the Mount Desert hUls for any trace of terraces, 

 but have failed to find them even in their most obscure form. 



