In turn , it flows north up to the south shore of Lake Memphremagog which discharges into the Magog River to Quebec .
The latter flows southwest , then northwest to the East bank of the Barton River .
It flows north up to the south shore of Lake Memphremagog which discharges into the Magog River to Quebec .
The latter flows southwest , then northwest to the East bank of the Barton River .