The Coastal Plain blankets the eastern flank of North America from Mexico to New York City. However, from Connecticut north into Canada there is no coastal plain.

Plain, and the submerged portion is called the continental shelf. But from Connecticut north into Canada, the edge of the coastal wedge lies just offshore, submerged by the ocean. Only on parts of Long Island, Block Island, and Cape Cod do coastal wedge sediments emerge from the ocean. The removal of the Coastal Plain accounts for the abrupt change in the character of the East Coast that takes place in Connecticut and New York.

Admittedly, the hills that stand by Connecticut's shore usually are not very large or dramatic, with the exceptions of East and West Rocks in New Haven and Lantern Hill in North Stonington. The small size of the hills has caused some confusion - several state publications and at least one map published by the United States Geological Survey show a coastal plain for Connecticut. This confusion probably is due to a misinterpretation of what Connecticut really has: the Coastal Slope. As was discussed in Chapter 3, the hilltops of Connecticut rise to a more or less planar surface that slopes gently from north to south at 10 to 20 feet per mile. But about 12 miles north of the Coast, this slope suddenly steepens into the Coastal Slope, with a drop of about 50 feet per mile. When the Coastal Slope plunges into the Sound, the altitude of the hills is down to only 50 to 100 feet. The hills are there, but there isn't very much to them.

Geologists believe that the Coastal Slope represents an area of southern New England that was once covered by loose sediments from the now-absent Coastal Plain. The temporary blanket of sand protected the seaward flank of southern New England's bedrock from the forces of erosion. Like a creature in hibernation, the bedrock surface lay sleeping under the ground while weather brought erosion to the rest of the region. Later, erosion washed away the loose coastal plain sediments, reexposing the bedrock surface that geologists call the Coastal Slope. Because of this period of protection, erosion has not had time to carve its name so deeply into the Coastal Slope, giving it a more level landscape than the rugged hills farther inland.

The gentler topography of the landscape makes farming much easier than in the rest of the Uplands and contributed to the high agricultural productivity of colonial farms along the Coastal Slope. In

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