The Damariscotta middens are notable for their size and their many oysters by a stream that has few today. The large presence 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 influenced 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. 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 overtaken 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 sawmill 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 ==