. A complete geography. , and San Francisco bays, as well as the manyexcellent harbors of the East. What rivers carved out the baysmentioned? (See maps, Figs. 44, 46, and 67.) One reason for so few good harbors along the coast of the South-ern States is that the land in this section has been rising out of thesea. Just off the coast is a broad ocean-bottom plain where the wateris shallow (Figs. 45, 68, and 96), while still farther out, the bot-tom slopes rapidly and the ocean becomes very deep. Upon this sea-bottom plain, called the continental shelf, layers of rock bits, or sediment, are being
. A complete geography. , and San Francisco bays, as well as the manyexcellent harbors of the East. What rivers carved out the baysmentioned? (See maps, Figs. 44, 46, and 67.) One reason for so few good harbors along the coast of the South-ern States is that the land in this section has been rising out of thesea. Just off the coast is a broad ocean-bottom plain where the wateris shallow (Figs. 45, 68, and 96), while still farther out, the bot-tom slopes rapidly and the ocean becomes very deep. Upon this sea-bottom plain, called the continental shelf, layers of rock bits, or sediment, are being de-posited, much as layersof rock were formed onthe sea bottom duringthe coal period. If thecontinental shelf shouldbe raised, it would forma great level plain. That part of theSouthern States whichborders the Gulf ofMexico and the ocean was once a portion of this ocean-bottom plain ;but it raised until it is now a low, level plain (Fig. 19).Since the continental shelf is so level, when a part of it was lifted. Fig. 19. A part of the raised sea bottom which forms the levelplain of Florida. PHYSIOGRAPHY OF NORTH AMERICA 15 above the water there were few places for deep inlets, bays, andharbors. After bemg raised, the coast was slightly lowered ; butthe bays thus formed are shallow and the harbors poor. The level plain of the Florida peninsula is also a sea bottom thathas been lifted above the ocean. Many of the lakes and swamps whichabound in that region are believed to be due to the shallow basinsbuilt by the irregular deposit of sediment on the old sea floor. Size, Shape, and Position. — North America is third in size amongthe six continents of the earth. By reference to the tables in theAppendix, find which are larger and which smaller. After being changed in shape during millions of years, owing tothe rising and sinking of the land, it at present has the form of atriangle with the broadest portion in the north. Draw the its shape with that of Sou
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectgeograp, bookyear1902
