3/0 APPENDIX TO PARTS I AND IT. 



tains also, for in the study of geography we are not to be confined to the limits of the 

 United States. So far as appropriateness is concerned, we may as well include the Lab- 

 rador as the White Mountains under the name Appalachian, — in fact, we must. Guyot, 

 in his Physical Geography (1873), has perceived this difficulty in terms, and uses the 

 name Atlantic highlands to include all the elevated region adjoining the eastern coast, 

 and places the Adirondacks with the Appalachians, calling attention to the plain east 

 of them. Harper's School Geography follows Guyot in using the terms Atlantic and Pa- 

 cific highlands for the mountainous regions on the two sides of the continent. 2. The 

 merging of these two systems under one name has been facilitated also by false theo- 

 retical notions. The advocates of the metamorphism of New England rocks legiti- 

 mately assume the Atlantic to be of the same age with the Appalachians. If their 

 doctrines were correct, this conclusion would follow. 3. The suggestion of the use of 

 the term Atlantic for the eastern portion of this mountainous district is intended to be 

 for geologists, not geographers. The eastern border will then have its Laurentian, 

 Atlantic, and Appalachian systems of mountains formed in three separate sets of peri- 

 ods, the Eozoic, early and late Paleozoic. There will be further sub-divisions of these 

 three systems developed as the subject is further studied. 



History of the Atlantic Mountain System. 



The place of this system of elevation will be further appreciated after a brief sketch 

 of the several important features of the physical history of the belt of land east of the 

 Appalachian valley from Newfoundland to Alabama. 



1. The original sediments of this area, now converted into rocks, were deposited in 

 a basin of Laurentian rocks, the Adirondacks on the west, and near the coast an 

 eastern line of similar age. The breadth of the eastern rim was greater at the south 

 than in the north. 



2. Precisely how far our porphyritic gneiss, Bethlehem and Lake Winnipiseogee 

 groups are coeval with the Laurentian, is not certain; but it is clear that the Montalban 

 rocks followed them, and that the first epoch of elevation occurred after their deposi- 

 tion. The first decided evidence of disturbance is afforded by the Franconia breccia. 



3. The whole Huronian period next intervened. New Hampshire does not afford 

 any evidence of elevation where the Montalban and Huronian rocks meet. The next 

 upheavals were in connection with the disturbances accompanying the formation and 

 intrusion of the Pemigewasset granites of Conway, Albany, and Chocorua, and the 

 porphyry. This was evidently the epoch of greatest disturbance known in the White 

 Mountains. It is to be compared with the elevation of the Green Mountains, where 

 the Cambro-silurian formations have been folded and faulted. 



4. There seems to have been, next, a submergence giving rise to the Gulf of St. Law- 

 rence and to the Appalachian valley, unless this movement was connected with the 

 Green Mountain elevation. 



5. There was also a time of depression all over northern New England, to allow of 

 the accumulation of Helderbcrg limestones. This was followed by, — 



