104 Part II. Chapter 1. 
These are separated by the Connecticut River, which drains south into Long 
Island South. In Maine, the White Mountain system has little coherence. 
Isolated peaks are the rule. Mount Katahdin is the dominating elevation 
5215 feet (I5go m), rising abruptly from the surrounding country filled with 
enumerable ponds and lakes. In New Hampshire, the White Mountains are 
grouped around various central points, Mt. Moosilauke, 4810 feet (1462 m), 
Mt. Lafayette, 5290 feet (1602 m) and Mt. Washington, 6290 feet (1918 m). 
With the exception of a narrow belt of Mesozoic rocks in the Connecticut 
valley, and a limited depösit of late Tertiary age on the eastern boundary of 
Lake Champlain and on the Atlantic Coast, there are, so far as known, no 
rocks in the New England district more recent than the Palaeozoic. Western 
Vermont and Massachusetts have rocks of lower Silurian age. Upper Silurian 
rocks occur in the Connecticut valley, New Hampshire, eastern Massachusetts 
and a large part of Maine. In northern Maine, traversing the state in a wide 
belt, rocks of Upper Silurian and Lower Devonian age are found. 
The Adirondack Mountains are topographically separated from the 
rest of the Appalachian ranges and belong to a geologically older system. 
The rocks are all eruptive, gabbro and granitic in character. Sedimentary 
beds occur along the edges of this system especially the eastern margin. 
Mt. Tahawus or (engl.) Mt. Marcy, 5344 feet (1638 m), is the dominating peak 
of a region noted for its lakes, lying at an elevation of 1500 to 2000 feet 
(456—608 m). 
Beginning with the Catskill mountains, the orographic and geologie 
peculiarities of the Appalachian system of Mountains begin to be more 
clear. In Pennsylvania the characteristic features of the range are developed. 
The first feature is the collection of eastern ridges known as the Blue Ridge. 
The second is the central valley variously folded and in which the sequence 
of the sedimentary deposits is discernible, and third, a system of mountains 
and tablelands to which the name of Alleghany has been given. 
The Great Valley is an important feature in both Pennsylvania and Vir- 
ginia and its drainage is complicated. The streams of the northern Appala- 
chian ranges are not controlled by the mountains. Two rivers rising in the 
Alleghany plateau far west of the Alleghany front join in the heart of the 
mountains of Pennsylvania to form the Susquehanna which empties into 
Chesapeake Bay. The headwaters of the Potomac lie in the plateau west of 
the Alleghany mountains and its principal tributary, the Shenandoah, is the 
largest river north of Tennessee, flowing in the direction of the length of the 
Appalachian valley. New River, which rises in North Carolina, chooses & 
difficult way to the Ohio River across the Great Valley and the Alleghany 
plateau. 
These features are accentuated in the South, notably in North Carolina, 
where the Appalachian system is not a unit, but is a complex containing 
features of nearly equal topographic importance. These are ı. the Blue Ridge, 
2. the eastern Monadnocks and Piedmont valleys, 3. the Unaka range, 4- the 
