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The earliest cultivated plant in North America is the bottle gourd, remains of which have been excavated at Little Salt Spring, Florida dating to 8000 BCE. [7] Squash (Cucurbita pepo var. ozarkana) is considered to be one of the first domesticated plants in the Eastern Woodlands, having been found in the region about 5000 BCE, though possibly not domesticated in the region until about 1000 BCE.
For reasons that are unclear, approximately 500 years ago, aboriginal populations declined significantly throughout Eastern North America and more broadly throughout the Americas. … Thus, by the time the first European observers were reporting the nature of the vegetation of the region, it is likely to have changed significantly since the ...
The Mitchell Map. The Mitchell Map is a map made by John Mitchell (1711–1768), which was reprinted several times during the second half of the 18th century. The map, formally titled A map of the British and French dominions in North America &c., was used as a primary map source during the Treaty of Paris for defining the boundaries of the newly independent United States.
Maps of the New World had been produced since the 16th century. The history of cartography of the United States begins in the 18th century, after the declared independence of the original Thirteen Colonies on July 4, 1776, during the American Revolutionary War (1766–1781). Later, Samuel Augustus Mitchell published a map of the United States ...
On land, North America's vegetation included plants like conifers, cycads, ferns, ginkgoes, and horsetails. [46] The Triassic vegetation of the east coast indicated swampy conditions in the local rift valleys. Arizona was home to a great forest that would later leave behind the area's famous petrified wood. [51]
The United States began expanding beyond North America in 1856 with the passage of the Guano Islands Act, causing many small and uninhabited, but economically important, islands in the Caribbean Sea and the Pacific Ocean to be claimed. [4] Most of these claims were eventually abandoned, largely because of competing claims from other countries.
Age of the bedrock underlying North America, from red (oldest) to blue, green, yellow (newest). Seventy percent of North America is underlain by the Laurentia craton, [5] which is exposed as the Canadian Shield in much of central and eastern Canada around the Hudson Bay, and as far south as the U.S. states of Michigan, Wisconsin, and Minnesota.
These glaciers destroyed any vegetation in their path, and cooled the climate near their front. Pre-existing natural communities remained largely intact south of the glaciers, but saw an increase in dominance of pine and a now-extinct species of temperate spruce, (Picea critchfieldii).