The friction aroused by repeated boundary disputes prevented friendly relations between Canada and the United States. With unconscious irony the framers of the Peace of 1783 had prefaced their long outline of the boundaries of the United States by expressing their intention "that all disputes which might arise in future on the subject of the boundaries of the said United States may be prevented." So vague, however, were the terms of the treaty and so untrustworthy were the maps of the day that ultimately almost every clause in the boundary section gave rise to dispute. As settlement rolled westward one section of the boundary after another came in question. Beginning in the east, the line between New Brunswick and New England was to be formed by the St. Croix River. There had been a St. Croix in Champlain's time and a St. Croix was depicted on the maps, but no river known by that name existed in 1783. The British identified it with the Schoodic, the Americans with the Magaguadavic. Arbitration in 1798 upheld the British in the contention that the Schoodic was the St. Croix but agreed with the Americans in the secondary question as to which of the two branches of the Schoodic should be followed. A similar commission in 1817 settled the dispute as to the islands in Passamaquoddy Bay. More difficult, because at once more ambiguous in terms and more vitally important, was the determination of the boundary in the next stage westward from the St. Croix to the St. Lawrence. The British position was a difficult one to maintain. In the days of the struggle with France, Great Britain had tried to push the bounds of the New England colonies as far north as might be, making claims that would hem in France to the barest strip along the south shore of the St. Lawrence. Now that she was heir to the territories and claims of France and had lost her own old colonies, it was somewhat embarrassing, but for diplomats not impossible, to have to urge a line as far south as the urgent needs of the provinces for intercommunication demanded. The letter of the treaty was impossible to interpret with certainty. The phrase, "the Highlands which divide those rivers that empty themselves into the river St. Lawrence from those which fall into the Atlantic Ocean," meant according to the American reading a watershed which was a marshy plateau, and according to the British version a range of hills to the south which involved some keen hairsplitting as to the rivers they divided. The intentions of the parties to the original treaty were probably much as the Americans contended. From the standpoint of neighborly adjustment and the relative need for the land in question, a strong case in equity could be made out for the provinces, which would be cut asunder for all time if a wedge were driven north to the very brink of the St. Lawrence.