The Montagnais Mission.
This was centered at Tadoussac, and ministered to the Montagnais, Bersiamites, Porcupines, Oumaniwek, Papinachois, and other tribes of the Lower St. Lawrence and the Saguenay. Tadoussac had, from the earliest historic times, been a favorite harbor and trading-station for the French; for, being at the junction of two great rivers, it was convenient as a place of assembly for the natives of the lower country. The first priests in the district had said mass there; but it was not until 1640 that a Jesuit mission was formed by Father Jean du Quen, its sphere of influence soon reaching to the upper waters of the Saguenay, Lake St. John, Hudson Bay, and the coast of Labrador. Du Quen was actively assisted by Charles Meiachkwat, a Montagnais convert, who erected the first chapel, became a catechist, and made extended tours through the neighboring tribes. In time, there were associated with Du Quen, Fathers Buteux and Druillettes. Protracted missionary tours were made by them, with results which were considered satisfactory as compared with other missions; although they had serious difficulties to contend with, in the prevalent intemperance which the fur trade introduced among the natives, the belief in dreams, the laxity of morals, and the wiles of medicine-men, or sorcerers, as they were called by the Jesuits.
Link (here) to The Jesuit Relations and Allied Documents