User:Nhyman22/sandbox

Introduction
Whaleback Shell Midden is a shell midden, or dump, consisting primarily of oyster shells located on the east side of the Damariscotta River in Maine, United States. It is preserved as a Maine state historic site and was included as part of the Damariscotta Oyster Shell Heaps listed on the National Register of Historic Places in 1969. Other shell middens are located on the estuary in both Damariscotta and Newcastle. The middens in this area were formed over about 1,000 years between 200 BC to AD 1000.

The midden originally had three main layers of shells. In the bottom two layers, individual shells were generally 5 - 8 in long. These two layers are separated by a layer of soil, and the middle layer is mixed with animal bones. The top layer contains smaller shells. Artifacts unearthed lead scientists to believe that successive tribes of prehistoric people used the area. The top layer was deposited by members of the Abenaki tribes that fished in the area in the summer.

Originally, the Whaleback midden was more than thirty feet deep, more than 1,650 feet in length, and a width varying from 1,320 to 1,650 feet. It got its name from its shape. Only a small portion of this midden remains today as much of it was processed into chicken feed from 1886 to 1891 by the Massachusetts-based Damariscotta Shell and Fertilizer company, was eroded by rising sea levels, or looted. Because of this, the Glidden midden, located across the river in Newcastle, is now the largest in Maine and the largest on the U.S. east coast north of Georgia.

Regional glaciation
Early people in Maine were significantly influenced by a changing climate around them, a climate that was largely shaped by glaciation. Before the shell midden was created, the Late Wisconsinan Laurentide Ice Sheet (LIS) covered Maine's landscape 35,000 years ago, extending far into the ocean. As the ice sheet retreated, Maine's climate was undergoing deglaciation about 14.5-11kya. Due to isostatic rebound, sea levels were fluctuating immensely. At the start of the deglaciation, the sea level was much higher inland ; the landscape at the time would have resembled northern Alaska. This impacted the culture of people by promoting hunter-gatherer dynamics that could respond more quickly to changing climates. It would be expected that early inhabitants would have roamed around the terrestrial landscapes hunting herds of animals. As the glacier retreated, sea levels dropped substantially, as low as 180ft below what we now recognize as the coast of Maine. Different geological processes continued to take place, raising the sea level quickly and then slowly into what we now recognize today.

Geology of Damariscotta
The Damariscotta middens are notable for two reasons: 1) their size, and 2) the large presence of oysters in the midden despite their being few oysters in the river. The second reason is connected to coastal change, sea level rise and the geology of the region. The midden is located between two sills, Johnny Orr and Indraft. These sills, volcanic in origin and most likely millions of years old, have had a large influence on the salinity and temperature of the river. In fact, on the oceanside of the Johnny Orr sill, the level of the water at high tide is higher than the level on the riverside.

The Eastern oyster (Crassostrea virginica) makes up a large portion of the shells located in the middens. However, oysters are not present in significant populations in the river today. This has led geologists to the understanding that at some point in time, there was a great deal of change occurring on the banks of the Damariscotta River that influenced the creation of such substantial middens. Oysters tend to like warmer, brackish waters – at some point in time, salty, cold oceanic water breached the Johnny Orr sill, mixed with warmer, less salty riverine water and created an environment that could sustain oyster populations about 2400 B.P. . The water may have breached the sill as sea levels were slowly rising. The reason for the water coming over the sill still remains a gap in the story of the Damariscotta River.

Though oysters do still exist buried underneath silt near the middens, significant oyster populations no longer exist within the river due to four possible reasons: 1) predator introduction , 2) suffocation from the dust of the saw mill upshore  , 3) increasingly saline environments , and 4) lower water temperatures. In all likelihood, it was probably a combination of all of these factors. Damariscotta is just another example of how changes in the climate have influenced human realities.

Threats to middens
Over 2,000 other middens exist along the Maine coast but many of their locations are undisclosed due to fear of looting. Unfortunately, looting is not the only threat they face. As sea levels rise due to climate change, middens like Whaleback are swept away to the ocean.