Text Box: New England Introduction | Mountains | More Features | Resources
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
                                                                                                                                                            
The New England province consists of nearly all of the mainland portion of the United States that lies east of the Hudson River Valley and Champlain Lowland.  The only exclusion is the Cape Cod region of eastern Massachusetts, which is part of the Atlantic-Gulf Coastal Plain province.  Additionally, the New England province has an extension west of the Hudson River Valley, the Reading Prong (also locally called the Highlands), an arm 140 miles long with a maximum width of 25 miles, extending to the southwest from southern New York to Reading, Pennsylvania. 
New England is primarily a plateau with several mountain ranges and individual peaks.  Much of the province has several structural characteristics in common with the Piedmont Plateau province to the south, especially dominant rock types.  However, the New England area has much greater topographic relief–nearly 6,000 feet, is also more mountainous, and experienced more volcanic and glacial activity compared with the Piedmont Plateau. 
Most of New England is composed of metamorphic rocks, the majority of which have been strongly and complexly folded and faulted.  This is indicative of the widespread metamorphism that accompanied the orogenies that have affected the area.  The Reading Prong extension is predominantly gneiss.  This rock type also forms the cores of several mountain ranges, including the Green Mountains of Vermont.  Sedimentary rocks overlay some of the Reading Prong and occur in a few of the more prominent valleys, such as Connecticut Valley and the Valley of Vermont.  A significant amount of granite and some basalt are also present.  A large portion of the White Mountains in New Hampshire and Maine developed on a large granite pluton, and some coastal cliffs and islands along Maine are partially granite.  Basalt occurs most notably over some of the sedimentary rocks of the Connecticut Valley. 
 
Glaciation
Virtually all of New England bears the imprint of continental glaciation.  The last major advance of continental glaciers in North America during the Pleistocene, called the Wisconsinan (and Wisconsin and Wisconsinian) glaciation, produced mile-thick glaciers that smoothed even the highest peaks in the White Mountains, the tallest range in New England.  Despite the ubiquitous effects of ice, the glacial history of the region has been more difficult to decipher than that of the Midwest.  Glacial till in hilly New England is much less continuous than it is in the relatively flat center of the country, and end moraines are scarce because the glacier terminated south of the province in areas now submerged by the Atlantic Ocean.  Other depositional landforms common in ice marginal zones are also now submerged by rising sea level in post-glacial time.  This submergence is also one reason why the effects of glacial erosion are much more apparent than depositional effects over much of New England. 
Some of the more visible erosional effects include the many rounded peaks throughout the province.  All of the major mountain ranges–White, Green and Taconic mountains–and Mt. Katahdin and Mt. Monadnock, have rounded summits.  Most of the nearly 2,500 lakes in Maine, and many of the lakes in other New England states, especially New Hampshire, are in glacially-carved basins.  The intricately indented Maine coastline was produced by erosion of the rock by ice, gouging a water-contact coastline of nearly 3,000 miles from an otherwise straight-line coast of 230 miles.  Maine and New Hampshire also have the preponderance of roches moutonnées in the region.  Other erosional effects include linear striations and grooves in the bedrock of many locations produced by glacial scouring, U-shaped valleys, and several examples of stoss-and-lee topography, including some relatively large hills and coastal cliffs that were significantly steepened on the lee (south) side by ice-plucking.  The Vermont Valley between the Green Mountains to the east and the Taconic Mountains to the west, was strongly carved by the ice, leaving it steep-sided, and broader than before the passage of the glacier.  Erosional effects were not only produced by the continental glacier,  but also by alpine glaciers that developed on the higher elevations before and after the continental glacier covered the region.  The northern, southern and especially eastern sides of the Presidential Range in the White Mountains have cirques, locally called ravines or gulfs, including Huntington Ravine, and Tuckerman Ravine, the latter having a headwall 800 feet in height on the southeast side of Mt. Washington.  The cirque called the Great Gulf,  also on the eastern side of the Presidential Range, has an imposing 1,500-foot-high headwall.  Many significant cirques also exist on Mt. Katahdin in Maine. 
Although glacial erosional features are generally more conspicuous than depositional features, many of the latter occur throughout New England, including some well-known landmarks.  Plymouth Rock, the boulder reported to have been the landing spot of the Pilgrims that arrived on the Mayflower, and later became a symbol of freedom for the early colonists  and is now a National Historic Landmark in Plymouth, Massachusetts, is a glacial erratic.  The Madison Boulder, southwest of Conway, New Hampshire is the largest erratic in New England, measuring 83 feet long, 25 feet wide and 37 feet high.  Bunker Hill in Boston, and nearby Breeds Hill (on which the Battle of Bunker Hill was actually fought and where the Bunker Hill Monument is located) are both drumlins.  Other drumlins occur in Boston, including some that today stand as islands in Boston Harbor and many drowned ones on the harbor bottom.  However, true drumlins, which are depositional–composed of glacial drift–are not especially numerous in most parts of New England, but there are thousands of rock drumlins–composed of bedrock in the form of a drumlin with a veneer of glacial till–that are particularly abundant in Massachusetts.  True drumlins are most common in Massachusetts, southeastern New Hampshire and in Maine.  Eskers are also especially abundant and large in Maine.  Some are more than 100 feet high and exceed 1 mile in width.  One of the Kennebec eskers, in the southwestern portion of the state, is 230 miles long.  Although eskers are relatively uncommon in New Hampshire and Vermont, one near St. Johnsbury, Vermont is 24 miles long.
Much of the province is covered with glacial drift, which is as much as 400 feet thick in some valleys.  The Vermont Valley contains a significant amount of glacial drift, which today provides economically important sand and gravel.  Many of the picturesque rock walls so common throughout New England were built of rocks strewn across the landscape by the advancing and retreating glaciers.  There are four large moraine belts in northeastern Vermont and well-developed moraines in northern New Jersey; moraines are better developed in these places than in many other places in the province partly perhaps because of the relatively lower relief.  There are also other depositional features in the province, including outwash plains, kames, kame terraces, and kettleholes. 
The mile-thick continental glacier that blanketed all of New England depressed much of the land several hundred feet.  Some drowned valleys along the Connecticut coast and at Boston are presently 250 feet below sea level.  The depression of the coast of Maine was sufficient for the ocean to penetrate inland to Augusta and Bangor; Augusta now is about 33 miles from the ocean.  Since the melting of the glacier from this region approximately 10,000 years ago, the land has been slowly rising through the process of isostatic rebound, for most of the intervening time.  Some of the earthquakes that occur in the region have been attributed to the warping that has resulted from the rebound (although perhaps some of the seisms, such as those of 1638, 1727 and 1755, may have been related to faults associated with former rift valleys created by Atlantic Ocean rifting).  However, the New England coastline has recently been subsiding slightly, partly because of the weight of sediment deposited on the continental shelf by rivers issuing from the interior.  Additionally, a global rise in sea level of about 5 inches over the past century has affected the coast.  Although the isostatic rebound of the New England region has not yet equaled the amount of crustal depression produced by the glaciers, the present subsidence coupled with sea level rise are causing a slight innundation along the coast. 
 
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