The Ferguson Rifle (Louis L'Amour's Lost Treasures)

It began with gold that had once belonged to Montezuma. Stolen and cached in a church in Mexico, it was recovered by two army officers who fled north for the French settlements. Along the way one stabbed the other to death. The remaining officer was eventually killed by Plains Indians, but he buried the treasure just before he died. Now Ronan Chantry, a handful of trappers, and an Irish girl whose father was killed after telling her a few vague landmarks are searching for the lost treasure. But they are not alone. The girls uncle, Rafen Falvey, wants it, too. Like Chantry, he is well educated, bold, and determined. Under different circumstances the two men might have been friends. But in all likelihood it wouldnt have made any difference. When it comes to gold, even friendship doesnt keep men from killing each other.