Перевести: the north-eastern atlantic coast is rocky but its middle and southern part rises gently from the sea passing from swamps into a rolling lowland. the usa is crossed by the appalachian mountains in the east and the rocky mountains in the west. the appalachians are not high but steep. the rocky mountains are high sharp and rugged and are rich in such minerals as gold copper and silver. they are the main mountains of the cordilleran highlands.