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The historical development of the river


The Lehigh Valley was entirely different billions of years ago. In fact, it did not exist at all and consisted entirely of a flat stretch of land with no animals or trees and little vegetation. Approximately 600 million years ago, a huge stretch of land broke apart into a western section (North and South America) and an eastern section (Europe and Africa). The area between these two landmasses, known as the Appalachian Sea, covered the Lehigh Valley at the time. Coral deposits, which have been found dating back 250 million years, have led scientists to believe that the Lehigh Valley area was part of a tropical inland sea. The simple creatures and algae in the area at that time combined with seawater and minerals to form clay, slates, and limestone. This allowed the Lehigh Valley to become a major source of natural resources (Hall and Hall, 1982).

Throughout its history, the area had various dramatic changes to face. The movement of the earth’s plates caused the land to buckle and the Appalachian Mountains to form. The waters which had once covered the region flowed away and were replaced with swamps and forests. Various reptiles and plants began to inhabit the area, but disappeared after an ice age swept over North America 150 million years ago. Huge glaciers and ice covered the region, causing the plant life to die and decompose. Eventually, the plant life transformed into the coal beds that lie to the north of the Valley. Many years later, these coal beds would become the source of many jobs in the Valley, helping to feed hungry mouths (Hall and Hall, 1982).

Eventually, the glaciers began to recede and animals that had once lived at the edge of the glacier began to enter the North American continent. These included caribou, bison, and wooly mammoth. Hunters followed the animals because they provided a source of food and clothing. Scholars believe that the first humans, known as Paleo-Indians, entered the Lehigh Valley about 10,000 years ago. This is because the remains of a mastodon, an animal hunted by the Paleo-Indians, was found at Marshall’s Creek near the Delaware River Gap. It dated back to 10, 210 B.C. These Paleo-Indians are thought to be the ancestors of the Lenni Lenape Indians (Hall and Hall, 1982).

The recession of the glaciers not only had effects on plant and animal life in the Lehigh Valley, but on the topography of the area as well. As the Wisconsin Glacier which covered the area receded, the melting ice gave way to rivers and streams, which dug into the land that had long been covered by the glacier. Eventually, the Lehigh River Watershed was formed (Hall and Hall, 1982).


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