370 APPENDIX TO PARTS I AND II. 
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 Helderberg limestones. This was followed by,— 
