452 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



beth rises to about 150 feet, and at about an equal depth, 25 fathoms, 

 the traces of this formation are lost in the oeean. 



The Coast of Maine. — From Portland to Eastport the coast of 

 Maiue has that characteristic appearance which we only find in the 

 coast line of high latitudes on both continents, which we attribute to 

 attrition by ice and call the fiord formation. Fiords are essentially a 

 succession of narrow channels, seldom exceeding one or two miles in 

 width, with parallel sides and running in approximately parallel direc- 

 tions. These channels are generally separated by equally narrow pen- 

 insulas or ranges of islands. The inclination to parallelism is, in general, 

 sufficiently pronounced to enable us to detect these regions by a mere 

 inspection of the charts. 



Assuming with Professor Dana, and the late Prof. Louis Agassiz, 

 that these tiords have been excavated above the level of the sea by the 

 grinding action of bases of glaciers, we find that the coast of Maine 

 must have stood about 50 fathoms above its present level when its fiords 

 were being shaped, since they extend to about that depth below the 

 present level of the sea. In many places we find this depth exceeded, 

 notably in the case of important channels. In the channel of Penobscot 

 Bay we have depths of 83 fathoms; but we can account for these con- 

 tradictions without casting loose from the glacier theory by making al- 

 lowance for the weight of a glacier making itself felt to some distance 

 into the sea and by assuming the occurrence of gorges in the defiles of 

 long channels. 



In studying the effects of glacial action upon the configuration of the 

 coast of Maiue we have to draw a distinction between the movements 

 of large continuous masses of ice in a uniform direction independent of 

 the shape of the ground and the motiou of local glaciers dependent upon 

 the shape of the ground. To the former we must ascribe the stria? in 

 the rocks about Portland and elsewhere, the general shape of the islands 

 off the coast and of the hills and mountains along the coast, and a'so 

 the more important river channels. Most probably there was a gradual 

 transition from the great "continental glacier" to local glaciers, and 

 the work commenced by the former received its finishing touches by 

 the latter. 



The prevailing directions of the striae and fiords on the coast of 

 Maine are south and south-southeast. Portland Harbor is a fiord chan- 

 nel, cut out of the slate strata of Cape Elizabeth, at an angle of about 

 60° to the strike of the rocks. East of the White Mountains, ranging 

 in height from 4,500 to 0,300 feet, the most conspicuous elevations on 

 the coast are the Camden Ilills, about 1,300 feet high, and Mount 

 Desert Island, 1,532 feet. Midway between the Camden Ilills and 

 Mount Desert we have Isle an Haut, 556 feet high. These hills must 

 have offered considerable resistance to the ice coming from the north- 

 ward, and hence we find the strongest traces of glacial action in the 

 vicinity of Penobscot Bay and Mount Desert Island. 



Mount Desert Eock. — This rock occupies the most isolated and 



