ON THE COAST OF MAINE. 333 



form such prominent features. So it is evident that the marks of glacial work coming from 

 a time anterior to the last ice period, however conspicuous in their day, would have been 

 in the main destroyed by the succeeding period. I cannot undertake to give a final answer 

 in the matter of the time at which the excavating work along the coast of Maine was 

 accomplished. Certain circumstances incline me, however, to the opinion that the ice 

 work was in a great degree done by glacial action anterior to the last glacial period. Of 

 these the most important is the following. 



If we examine closely the shore line wliere it is drawn along the rocky part of our coast, 

 say from Massachusetts Bay to Eastport, we find that everywhere there is a steep escarp- 

 ment bounding the land, which shows in every feature the work of the sea. The general 

 relation of this escarpment to the adjoining country is shown in Fig. 2. There can be no 

 doubt that this cut represents the wear- 

 ing of the sea acting continuously, and ^ 

 for great periods, at the same, or near 



the same, level. But it is evident that Y////////////////^/777>^^ 



the last glacial period found the shore in //////////////////////////777yir-r-r~ 

 much the same form as at present, for, Fio. 2. 



except when the rock is very crumbly, a. The escirpm.-nt made by the action of the sea generally 



or exposed to the severest beat of the s"''"'^'' ^^ ''"^ ''-"'^ °^ 'l^e '='**■ i;''^^'''' t'"!*-'- 



. . 1 -ii ii • /> «• Sea level. 



waves, it IS covei-ed with the scoring 01 



the ice sheet. Now if the wearing brought about during the glacial period did not exceed 

 the few feet which would have been required to erase the old shore line, it is evident it 

 could not have sufficed to dig out the great fiords along which that shore is traced. Yet the 

 valley's of the fiord section are as clear and sufficient evidence of ice work as the glacial 

 scratches themselves, and must be explained by the same agent. Thus it is seen, beyond 

 reasonable doubt, that between the time when the shore was formed and the present day, 

 the ice action which has occurred was relatively only slight, and could not have accom- 

 plished the greatest part of the ice work indicated by the topography of the region. At 

 first sight it would seem as if we might find an explanation by supposing that the shore 

 had been excavated between the first disappearance of the ice and the return of the 

 glaciers at the second stage of the period. But besides the evident difficulty of the length 

 of time between the two phases of the ice period which tliis hypothesis requires — a time 

 which, measured by the rate of cutting of the waves, must have been several times as great 

 as that which can be called post-glacial — there is the fact that in Massachusetts the second- 

 ary glacial period did not make any continuous sheet of ice whatever, Ijut only local streams 

 leadmg from the high land to\vard the shore in the principal river valleys. Even in nearly 

 the southernmost country where the ice came in a sheet to the shore, in the valley of 

 Narragansett Bay, we have the same glaciated coast, and the same sea beach scored and 

 grooved by the ice. It thus becomes evident that the topography of this country is due to 

 antecedent glacial periods having an effect far exceeding in aggregate amount the work of 

 the last of the series. Having proven more than one glacial period, it is easily seen that it 

 becomes probable that this work has been done by a number of successive ice-times rather 

 than by any one great period of this character. This view of the duration and severity of 

 the ice-time is in perfect accordance with what is known from other soiu'ces concerning the 

 condition of that time. Many students of the question of the origin and antiquity of man 



MEMOIRS BOST. SOC. NAT. HIST. VOL. H. 84 



