cordant at the new level. This is normal sea cliff and ter- 

 race feature enlarged to a gigantic scale. According to 

 Professor Barrell the sea would stand at a certain level long 

 enough to erode the coast miles inland. This was followed 

 by rapid retreat to a lower level where tiie process was 

 repeated. This stand was not long enough for the com- 

 plete destruction of the terrace above. Thus, by progressively 

 rapid retreat New England was carved into a series of steps. 

 As soon as a wave swept level was exposed to subaerial ac- 

 tion river and atmosphere erosion carved it into hills whose 

 tops still show traces of the old terrace level. 



Barrell in Connecticut, has recognized eight of these 

 wave cut terraces ranging in height from 500 feet to 2300 

 feet. He correlates these terraces with the erosion levels 

 of the coastal plain to the south. The terraces pass north 

 and north east but have not been studied north of the north- 

 ern boundary of Massachusetts. An extension of these shore 

 lines would pass into central and western Maine. A 

 great part of the state is still unmapped on the scale neces- 

 sary for the accurate determination of the wave cut benches. 

 In the southeastern part of the state there seem to be ac- 

 cordant hill tops at 300, 400, 700, 1100 and 1300 feet above sea 

 level. More careful work is needed to determine these levels 

 with exactness. 



We have now considered some of the evidence whereby 

 geologists have come to the belief that the Earth's crust un- 

 derlying New England has been unstable. In closing we will 

 briefly outline the geological history of Maine during Ceno- 

 zoic time as indicated by the wavecarved record. 



The beginning of the Eocene, the first period of the 

 Cenozoic Era, saw the greater part of Maine beneath the 

 sea. Probably the shore line was in the western part of the 

 state or even in New Hampshire. Here and there islands 

 or groups of islands rose above the waves. These were 

 the tops of the present mountains. In general appearance 

 the coast was not much different from that of today. The 

 whole of North America was unstable. In the extreme west 

 the mountain making movements which ended in the Cas- 

 cadian Revolution had already started. In the east this un- 

 rest showed in the gradual uplift of New England. The 

 movements were rythmic, a time of relative quiet being fol- 

 lowed by a period of rapid uplift. During the periods of 

 quiet the sea ate its way inland forming a nearly level sea 

 floor from which masses of resistant rock rose as islands. 

 Then, with renewed movement of the earth the sea would 

 retreat until a new period of quiescence allowed a new ad- 



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