Near Slitu, a gravel ridge stretches three to four kilometres across the landscape, towering 80 metres above the surrounding terrain. Monaryggen was formed roughly 10,000 years ago at the end of the last ice age, when a meltwater river carrying sand and gravel poured out of the glacier front into a still lake. The result is a fan-shaped delta formation, and it is the largest of its kind in Northern Europe.
The ridge also carries traces of a much later history. Across Monaryggen, 46 burial mounds have been recorded, three of them among the largest in Indre Østfold. The people who built them clearly recognized the ridge as a landmark worth marking.
Today, Monaryggen is being slowly consumed. Large gravel quarries have removed significant sections, and the E18 motorway cuts across it. What remains is still impressive, but the formation is visibly smaller than it once was.
The ridge also carries traces of a much later history. Across Monaryggen, 46 burial mounds have been recorded, three of them among the largest in Indre Østfold. The people who built them clearly recognized the ridge as a landmark worth marking.
Today, Monaryggen is being slowly consumed. Large gravel quarries have removed significant sections, and the E18 motorway cuts across it. What remains is still impressive, but the formation is visibly smaller than it once was.
