Geology
Glaciers from the last ice age carved out the path of Biigtig Ziibii. The ice scraped and scoured the ancient rock of the Canadian Shield. McKay Lake is one of the many inland lakes the glaciers formed that are not well drained. Biigtig Ziibi formed to drain the lake’s water to lower ground. The mouth of Biigtig Ziibii at Lake Superior flows through dramatic sand dunes, sharp rock faces, spruce forests, and muskeg.