Our information concerning this fort is very scanty, being confined to a simple mention of it with the name of its commander, in Tonty's memoir of 1693.[95] At the end of October, 1685, Tonty started from Mackinac in a canoe on Lake Michigan to go to Fort St. Louis on the Illinois River. Because of the lateness of the season his progress was rendered impossible by the formation of ice in the lake. This compelled him to return to Mackinac, whence he again set forth, this time by land, for Fort St. Louis. An earlier account of this trip than that of 1693, but of equal brevity, was written by Tonty in the summer of 1686.[96] It does not even mention Durantaye's "Fort of Chicagou," but it adds certain details concerning Tonty's trip which are of importance in determining the location of that establishment.
[95] French, Historical Collections of Louisiana, I, 67.
[96] Letter of Tonty to M. Cabart de Villermont, August 24, 1686, in Margry, III, 560.
Tonty was, of course, familiar by 1686 with both sides of Lake Michigan. In view of this fact it is extremely improbable that, having to go by land from Mackinac to Fort St. Louis in the winter time, he would make the long détour around the head of Lake Michigan and Green Bay and down the western side of the lake, rather than follow the shorter route down the eastern side and around its southern end. This reasoning finds support in the statements of Tonty of the distances he traversed. The entire distance from Mackinac to Fort St. Louis he gives as two hundred leagues, and states that after traveling one hundred and twenty leagues he came to Durantaye's fort. It was, therefore, eighty leagues from Fort St. Louis. The usual estimate of French travelers of this time of the distance between Chicago and Fort St. Louis was thirty leagues;[97] while the distance overland from St. Joseph to Fort St. Louis was approximately eighty leagues. It is incredible that Tonty would estimate the distance from Mackinac to Chicago by land at one hundred and twenty leagues, and that from Chicago to Fort St. Louis at eighty leagues, a distance two-thirds as great. The supposition that Durantaye's fort was on the St. Joseph River rather than the modern Chicago harmonizes well both with the probabilities of the case and the distances given us by Tonty.
[97] See for example St. Cosme's statement in Shea, Early Voyages Up and Down the Mississippi, 59.
The foregoing reasoning is not, of course, absolutely conclusive of the location of Durantaye's "Fort of Chicagou," It is strengthened, however, by one other consideration. If such a fort was in fact here in January, 1686, what had happened to it in the interval between this time and Cavalier La Salle's visit in the autumn of 1687? Joutel's narrative of the adventures of his party is given with a wealth of detail. Both in the autumn of 1687 and again in the spring of 1688 the traveler stayed at Chicago for several days. Not only does the narrative show that there was no garrison or fort here, but it contains no mention of such an establishment at any previous time.
The French had no fort at Chicago in the eighteenth century, then, and if they had one in the seventeenth century it could only have been a temporary, structure which quickly disappeared. It remains to suggest an explanation of the origin of the widespread belief that there was a French fort at Chicago. It seems evident that it was due largely to the cartographers, who, residing for the most part in Europe, found themselves at a loss to interpret correctly the narratives of the explorers, which were themselves oftentimes confused and inaccurate, or lacking in detail. That the cartographers often labored in the dark, and that their work was frequently erroneous, will be apparent from a comparison of their maps with those of an authoritative modern atlas. The representations of the map-makers can no more be relied upon implicitly than can the narratives of the time; and there is as much reason in the one case as in the other for subjecting them to critical scrutiny.
In the present instance the erroneous belief in the existence of a French fort at Chicago in the eighteenth century probably originated with Father Hennepin, the garrulous companion of La Salle. He had been at La Salle's Fort Miami on the St. Joseph, and had passed thence with his leader down the Kankakee and the Illinois. Yet his New Discovery, first published in 1697, contains a map[98] showing "Fort des Miamis" at the mouth of a stream emptying into the southwestern corner of Lake Michigan. It is obvious from a comparison of this map with the one in Hennepin's earlier work, the Description of Louisiana, published in 1683,[99] that this representation is intended for the St. Joseph River and La Salle's Fort Miami, which, by a stupid blunder, have been transferred from the southeastern to the southwestern side of the lake. The New Discovery enjoyed widespread popularity, and numerous editions were issued during the following years, not only in French but also in foreign languages. Hennepin's maps, too, were widely copied in other works, and so the blunder with respect to the location of Fort Miami was perpetuated. Evidently this was the source of the error of Logan and of the many who in later times repeated his statements. Ignorant alike of the fact that Fort Miami had stood at the mouth of the St. Joseph and that it had been destroyed nearly forty years before, Logan located it at Chicago in 1718, adding the interesting information that it "was not regularly garrisoned."
[98] For a reproduction of this map see Winsor, Narrative and Critical History, IV, 251; Hennepin, New Discovery (Thwaites ed.), I, (facing) 22.
[99] For a reproduction of this map see Winsor, op. cit., IV, 249; Hennepin, op. cit., I, frontispiece.