ON THE COAST OF MAINE. 323 



period, and the changes which immediately followed it, during which times the great 

 depression of our shores occurred, the ph^-sical influences must have been very much 

 against the existence of animal life in any abundance. We shall therefore have to rely, in 

 the main, upon the evidence which can be obtained from the non-fossiliferous gravels and 

 sands of the coast. 



The third sort of evidence of elevation which the shore line can ffive us, thoush not 

 without its value in the problem before us, we shall find to hold but a subordinate place. 

 We shall see that the duration of the suljsidence on the coast of Maine was not a-reat 

 enough to admit of a great amount of marine work, or at least that part of the time of 

 submergence during which the shore was bare of ice, and exposed to the wear of the sea, 

 was not long enough to permit any great amount of erosion. How slight it was luay be 

 inferred by tlie fact that along nearly the whole shore the glacial scratches, which 

 were certainly formed before the gravel beds were laid down in the stratified form which 

 so clearly evinces the action of the seas, are still unworn, down to the water's edge. 



This feature of the persistence of the glacial scratches, even to the margin of the sea, is 

 not by any means peculiar to the coast of Maine ; it is clearly seen at Newport, Rhode 

 Island, where the scratches, which seem to have had no protection against the action of 

 the weather, retain an admirable clearness, showing, beyond a doubt, tliat even in por- 

 tions exposed to the full brunt of the storms, the erosion was not enough to take even 

 a small fraction of an inch from the stone. Along the coast of Massachusetts we have 

 the same feature distinctly shown at various points. On Cape Ann, one of the most 

 exposed promontories of our stormy northern coast, the evidence is very clear. 



Taking then the beds of stratified drift as the only acceptable and abundant evidence of 

 depression, we must look at the question of the origin of these beds, and the possibility of 

 their Ijeing formed by other agents than those which are at work in the sea. Some slight 

 amount of stratification is certainly not inconsistent with the action of ice in the form of 

 extensive sheets, especially when we consider that the plainest mark of the ice woi'k would 

 be that left by the water derived from the melting of the glacial mass, as the conditions 

 changed to those which are now in action. But wlien the stratified drift is distributed in 

 extensive sheets of approximately horizontal materials along the shore, all doubt of marine 

 action may fairly 1)e put aside. 



The following account of an examination of the coast gives only those results which 

 have an important bearing on the question in hand ; many of the details which did not seem 

 important to the conclusions have been omitted. In order to reduce the work Avithin the 

 hmits of the time at my disposal, the study of the coast was taken up on the west shore of 

 Penobscot Bay, and continued along the main land to the eastward, as far as Machias, 

 Eastport, and Calais. On account of the greater range of height along this part of the 

 coast, the opportunities for tracing the history of a change of level are decidedly better 

 than on the coast from Portland to the Penoljscot. In order to acquaint the reader with 

 the general character of the phenomena to the southward of Maine, I shall take up the 

 sketch of the shore at Boston, Mass. 



The neighborhood of Boston, like the whole countrj' to the southward as far as New 

 York, is characterized by having a vast accumulation of drift materials disposed in four 

 distinct formations, each indicating a separate stage of the changes of the glacial j^eriod, 

 viz. : — 



