The western edge of the railway embankment marks the spot where ancient shell middens occasionally emerge from the eroding field edges; these heaps of discarded shells and other refuse offer valuable insights into the diet and daily life of the area's early inhabitants.

One of these middens has provided particularly significant evidence for understanding the site's antiquity. A sample taken from the deposits yielded a radiocarbon date of 5130±60 BP (Beta 155378), placing human activity here firmly in the Mesolithic period, roughly 5,000 years ago. This dating evidence, documented by researchers Woodman and Milner in the early 2000s, confirms that hunter-gatherer communities were exploiting the coastal resources of this part of Donegal millennia before the arrival of farming.

The shell middens at Blanket Nook represent just one piece of a broader pattern of Mesolithic occupation along Ireland's coasts, where communities took advantage of rich marine resources including shellfish, fish, and seabirds. Though the site might appear unremarkable today, these eroding traces of ancient meals continue to provide archaeologists with crucial information about Ireland's earliest inhabitants and their relationship with the sea.