North America is the continent located in a northern part of the Western hemisphere. As well as all modern continents, it appeared on Earth not at once, outlines of continents changed many times.
The most ancient continent created 3.6 billion years ago received the name Vaalbara. After its disintegration arose still more than once and again new supercontinents broke up: Ur, Kenorland, Nong, Rodiniya, Pannotiya. After Pannotiya's disintegration at the end of the dokebriysky period there was a continent Gondwana and also several mini-continents – Fennosarmatiya, Siberia and Lavrenti.
Lavrenti there corresponded the North American ancient platform which became in the future a basis of the continent of North America.
In the period of the Caledonian skladchatost (500-400 million years ago) of Lavrenti faces other ancient platform – East European. So the continent Lavrussiya is born. At the end of the Paleozoic, in the Permian Period, the new supercontinent - the Pan-gay is formed. As well as other ancient continents, Lavrussiya is a part Pan-gays. When forming this supercontinent on joints of platforms there were mountain systems, many of which exist and now. In North America the Appalachians belong to number of such ancient mountains.
Disintegration Pan-gays is the share of the Mesozoic, more precisely – of the Jurassic Period (201.3-145 million years ago). The supercontinent was split into two continents – Gondwana and Lavraziya. As a part of Lavraziya there was also ancient Lavrussiya, including Lavrenti – the North American ancient platform. Lavraziya in the Northern hemisphere settled down and united in herself, along with future North America, practically all territories which are in this hemisphere now, an exception were made only by the peninsula of Hindustan. For this reason the ancient continent also received such name representing a combination of the terms "Eurasia" and "Lavrenti". From the southern continent – Gondwana Lavraziya was separated by the Ocean Tetis which is extending in the east and narrowed in the West. Lavraziya's disintegration begins in the middle of the mesozoic period. Ancient Lavrussiya at the same time does not keep the outlines: The east European platform is a part of the new continent – Eurasia, and from Lavrenti, the North American platform, North America is formed. After Lavraziya's disintegration North America and Eurasia repeatedly connected among themselves the Beringovy isthmus arising on the place of the modern Bering Strait. These changes were connected with fluctuations of global sea level: when the level of the ocean fell, over the surface of the sea there was very extensive site of the continental shelf which width reached 2000 km. Beringov's existence of an isthmus allowed ancient people to move from Asia to North America, so there was an indigenous people of this continent – Indians. Last time Beringov an isthmus disappeared 10-11 thousand years ago, and it became "touch-up" to formation of modern outlines of North America.