Horizon I: 17,000-14,000 Years Ago A Glacial Lake Thousands of years before Cedar Swamp existed, a massive glacial ice sheet covered the land. As the ice moved, it picked up rocks and sediment and gradually sculpted the basin now occupied by Cedar Swamp.  When the glacier receded from Mashantucket approximately 17,000 years ago, an enormous piece of ice broke off. This block of ice slowly melted and created a cold, muddy glacial lake in the basin -- thus beginning the long and fascinating history of Cedar Swamp. 1. Block of Ice Surrounded by Glacial Lake Plain During its retreat, part of the glacier broke off and remained in Cedar Swamp basin. As this ice melted, it created a glacial lake. 2. Sand and Gravel Damming Lake at the North Tons of sand and gravel, seen in the core at this horizon, flowed in with streams carrying glacial meltwater and remained here as deltas, or sedimentary deposits. 3. Bleak Landscape When the ice retreated, cold winds blew continually over the bleak rocky landscape. There is no evidence that people lived at Mashantucket at this time. 4. Dispersed Plants Dispersed plants began to appear on the land surrounding the lake. 5. Dwarf Willow Dwarf willow (Salix herbacia) is another plant often found in tundra environments. Fragments of this species were found in the Cedar Swamp Core.