A CONCEPTION OF THE GLACIAL PERIOD IN MAINE 447 



came a period of local glaciation, which at first may have been from 

 several centers — as, for instance, from the Adirondack center, the Green 

 Mountain center, the White Mountain center, and the Ktaadn center — 

 with glaciers sufficiently extensive to reach well into the Saint Law- 

 rence basin, perhaps discharging icebergs, with their rock load, into the 

 enlarged bay of Saint Lawrence. The continued shrinkage of these 

 large centers gave rise to coalescing valley glaciers, which were finally 

 replaced by isolated, unconnected glaciers, such as those which occupied 

 the North and South basins of Ktaadn. 



This last stage certainly existed in the Ktaadn region, and from the 

 writings of others seems proved for the White mountains and elsewhere 

 in New England. Therefore, of this assumed history, some of the stages 

 are inferred, while others may be considered proved ; and that part which 

 is inference is strengthened by the fact that this order of events is that 

 which seems to have been followed in other similar regions. 



There is an admirable opportunity for further study of the glacial 

 geology of the northern Maine region, for in that region lies the key to 

 an understanding of some of the important events of the Glacial Period 

 in America. It will be by no means an easy study to make, since, aside 

 from the difficulties of traveling due to the forest cover, and from the 

 countless millions of insect pests which inhabit the forest, there is an 

 almost universal absence of cuts in the glacial deposits and an almost 

 complete burial of the bed rock. One may travel through the forest for 

 scores of miles without finding a rock outcrop; for, even when present, 

 the forest mould, moss, and fallen trunks conceal it from view almost as 

 completely as a soil cover would. Where the rock itself outcrops it has 

 been exposed to the weather so long that signs of glacial action have 

 been almost completely destroyed. The chance for study will be found 

 mainly in tracing the distribution of blocks of rock from the mountain 

 centers. Until that has been done the full history of this region can 

 not be written. 



Summary 



Mount Ktaadn is a granite mountain in northern Maine. It reaches 

 to an elevation of almost a mile above sealevel. Previous observers 

 have reported that the highest peak of the mountain bears no proof of 

 ice covering, and it has been inferred that it rose above the ice as a 

 nunatak. It is one of the objects of this paper to present evidence that 

 the ice did overtop Ktaadn. 



A second point of the paper is to show that, as a last stage of ice-action, 

 valley glaciers occupied the valleys on the east side of Ktaadn, building 

 well defined moraines, some of which inclose lakes. 



