GEOGRAPHY
Physical
Geography of the United States and Canada
Look at pages 117, 122 & 123 in the textbook.
*Canada is the 2nd largest country in the world, and the United States
are 3rd. Put together, the cover more than 7 million square
miles, or about 13% of the Earth’s land area (or just under 4% of all
the Earth’s surface).
*There are four major physiographic regions in the United States and
Canada: the Western Uplands, the Interior Lowland, the Eastern
Highlands, and the Eastern Coastal Plain.
*The westernmost region is the Western uplands system, a series of high
mountains and plateaus (and valleys and lowlands mixed in) that stretch
from Mexico to Alaska. They were formed relatively recently
(between 140 and 65 million years ago) by tectonic and volcanic
activity, and they still have a number of active volcanoes—the most
recent major explosion was at Mount Saint Helens in 1980, the most
deadly in US history, which blew off the entire side of the mountain,
killing 57 people and destroying 185 miles of highway. Since
October 2004, the mountain has been exhibiting minor volcanic activity
again.
*Unfortunately, most of this region, especially near the Pacific,
experiences significant earthquake activity.
*This region includes the Pacific Ranges, and the Alaska Range, which
includes the highest mountain on North America, Mount McKinley in
Alaska (20,320 feet above sea level). The Rocky Mountains are
also part of this region, and run from New Mexico to Alaska, with some
peaks over 14,000 feet above sea level.
*The western side of these mountains is generally very pleasant, thanks
to the maritime effect and the good side of the orographic
effect. Southern California enjoys a Mediterranean climate, with
dry summers and mild, wet winters. This lets it grow oranges and
cotton, and other crops that require such conditions.
*Farther north, Northern California, Oregon, Washington, British
Columbia, and parts of Alaska enjoy a Marine West Coast climate, and
parts of Washington are so well-watered that they actually produce a
temperate rain forest, where the redwood tree (and other tall trees)
are found.
*Between the Pacific Ranges and the Rockies are a series of plateaus
and valleys. Because of the orographic effect, most of this area
is fairly dry. Most of it has a steppe climate, and parts of it
are desert.
*The Colorado Plateau is in Western Colorado, which has been worn down
by erosion, features the Grand Canyon. It is suitable for some
ranching and grazing.
*This area is also where Death Valley, the lowest and hottest point in
the United States can be found (in California); it is 282 feet below
sea level, and reached a US record temperature (2nd hottest worldwide)
of 134°F on 10 July, 1913 (the hottest temperature ever was 136.4
°F in Libya in 1922).
*The space between the Pacific ranges and the Rockies also includes the
Great Salt Lake.
*The Rocky Mountains serve as the western continental divide for the
United States and Canada. East of the Rockies is a vast area of
interior lowlands. In the United States, this is the Mississippi
watershed.
*The Mississippi-Missouri River system is the fourth longest in the
world and by far the longest in North America.
*The northern part of this region has largely been defined by glacial
erosion, while the Southern part has been defined by water erosion and
river deposition.
*During the Ice Ages (the last of which ended about 10,000 years ago),
glaciers scoured much of the topsoil and loose rocks off of large
stretches of Canada and the northern United States. This pressed
the ground flat, to a greater or lesser degree, and in many places
carved out lakes.
*In Canada, the flattest and most scoured region (which lost most of
its best soil) is the area around Hudson Bay; it is known as the
Canadian Shield.
*Minnesota calls itself the land of 1,000 lakes (and Manitoba calls
herself the land of 10,000 lakes), and most of these lakes came from
glacial action, as did the Great Lakes themselves.
*Most of the soil scoured off of the Canadian Shield and elsewhere
ended up in the central United States, but some was left everywhere
there was glacial activity.
*Some of this soil was washed away by erosion, and ended up along the
Mississippi and its tributaries in their flood plains.
*About the only things that cannot be grown are citrus fruits and some
other tropical crops, and in the continental regions, cotton and rice
and a few other warm-weather crops do not do well.
*The best soil in the entire area is found in the region between Iowa
and Ohio
*This area feeds the United States, Canada, and large parts of the rest
of the world.
*In the United States, the Eastern Continental Divide is the crest of
the Appalachian Mountains, and the area around the Mountains is a
distinct region unto itself, although it is less complex than the
Western Uplands.
*The Appalachian Mountains were formed about 350 million years ago (or
possibly longer) through tectonic folding action when they were at the
centre of the super-continent Pangaea. They have been wearing out
ever since, and today their highest point is Mount Mitchell in North
Carolina, at 6,684 feet above sea level.
*The Appalachian Mountains stretch from Alabama up to Newfoundland,
although there are some breaks along the way.
*An area of raised land on the east of the mountains is called the
Piedmont (or foothills).
*The local range of the Appalachians is the Unaka Range, sometimes
known (especially farther South) as the Great Smokey Mountains.
The Unaka Range is part of the Blue Ridge, which runs from Georgia to
Pennsylvania.
*Between the Blue Ridge and the western plateaux lies the Great
Valley. It runs from the Saint Laurence River to Alabama.
Around here, this is where the Holston River runs down to the
Tennessee. The Great Valley system also includes the Shenandoah
Valley of Virginia, one of the most fertile regions in
Appalachia. The Great Valley is important historically because it
was the route many people took to settle the west, coming down into
Virginia and Tennessee from Pennsylvania.
*East of the Appalachian Mountains, and south of them along the Gulf
Coast, is the Eastern Coastal Plain. It stretches from New Jersey
down into Southern Texas.
*This was the area of the earliest settlement in the United States,
because it was closest to Europe, and, being relatively flat, was easy
to settle.
*The edge of early settlement was typically the edge of the tidewater,
and later the fall line.
*The Tidewater is a region in which the rivers near the ocean are
affected by the tides, in some cases so much that the flowing of water
in and out and high and low tide would be enough to move boats up and
down the river.
*The Fall Line is the place where the Piedmont drops off to the Coastal
Plain; it is the point where a river has not eroded the land down to
(or near) sea level. At or beyond the fall line, rivers become
shallow, rocky, or have waterfalls (hence, ‘fall line’). Many of
the USA’s great cities (Philadelphia, Baltimore, Washinton, D.C.) lie
on the fall line as a place where goods could be transferred from land
transportation to ships.
*In almost all of this region the climate is humid subtropical, even
giving way to some tropical savanna in southern Florida. This is
due in part to the presence of the Atlantic Ocean and its warm
currents. This region can (in lower places) see palm trees,
citrus and other warm-weather fruit trees, cotton, rice, and other
crops that require warm (and usually wet) weather.