In what direction did A. Mackenzie cross North America?

Sir Alexander Mackenzie is a Scottish traveler, native of the Hebrides. He crossed the Slave River towards the Arctic Ocean from the port of Chipevayan. In 1792 he walked along Lake Athabasca to the Lees River, while moving from the side of St. Lawrence Bay. Here he discovered two rivers, one south and one north. The south was chosen as a landmark, the traveler climbed to its source Parsip and went out along the Bella-Kula River to Queen Charlotte’s Bay. Thus, he crossed North America in a meridian direction.