The main pre-historical architect of the Harricana River and the Abitibi-Temiscamingue region is the large glacier which left its traces across the area many thousands of years ago during the last ice age.
This gigantic mass of ice coming from Labrador crossed the territory north to south. Because of warming weather about ten thousand years ago, it again crossed the region flowing towards the north. In receding quickly from the south the glacier carved several large ponds and rivers flowing north to James Bay and Hudson Bay.
The soil in Abitibi is made from deposits left by the glacier: there is a layer of moraine covered by an esker which is a layer of fine gravel and then a layer of clay. Long-term grinding and pulverisation has transformed the rocky material carried by the glacier into “rock flour”. This very fine material was deposited in the waters during the thawing of the glacier. Thousands of years later, a large part of the water receded and the clay that it contained was deposited onto the moraine and a part of the esker.
Harricana is an Algonquin word that means river of biscuits. The biscuits refer to the pebbles of clay formed over the millennium. These calcium deposits are also called “Fairy Stones”. They can be found in large numbers especially on the shores of Lake La Motte.