Among the many Christian denominations, Catholicism and Mormonism are unique. Orson F. Whitney, an early Apostle for the Church of Jesus Christ of Latter-Day Saints, shared a story of a Roman Catholic acquaintance who talked with him after delivering a speech at the Salt Lake Tabernacle. “I became well-acquainted with him, and we conversed freely and frankly. A great scholar, with perhaps a dozen languages at his tongue’s end, he seemed to know all about theology, law, literature, science and philosophy. One day he said to me: ‘You Mormons are all ignoramuses. You don’t even know the strength of your own position. It is so strong that there is only one other tenable in the whole Christian world, and that is the position of the Catholic Church. The issue is between Catholicism and Mormonism. If we are right, your are wrong; if you are right, we are wrong; and that’s all there is to it. The Protestants haven’t a leg to stand on. For, if we are wrong, they are wrong with us, since they were a part of us and went out from us; while if we are right, they are apostates whom we cut off long ago. If we have apostolic succession from St. Peter, as we claim, there is no need of Joseph Smith and Mormonism; but if we have not that succession, then such a man as Joseph Smith was necessary, and Mormonism’s attitude is the only consistent one. It is either the perpetuation of the gospel from ancient times, or the restoration of the gospel in latter days.”
His conclusion makes sense. Either the gospel has continued, uninterrupted, from the time of Christ’s apostles (Catholicism), or parts of it were lost and needed to be restored in the latter days (Mormonism). Fortunately, we can discover truth for ourselves through The Holy Ghost (or Holy Spirit), who is the great testifier of all truth. (John 15:26)

Except that the Book of Mormon does not contradict the Bible. It supports it.

There were not migrations over that entire time period. One group, called in the Book of Mormon the Jaredites, that migrated to the Americas when the Tower of Babel was destroyed. Another group, the family of Lehi and some associates migrated around 600 BC. They were called the Nephites, after Lehi’s son. One more recorded group was called the Mulekites. Mulek was a son of Zedekiah, probably very young, who was rescued from the invading Babylonians and taken to the Americas. All three migrations were led by revelation from God to this land. All three were small groups. After His resurrection Christ visited their remaining descendants to establish His church among them, although they had already looked forward to his coming and kept the law of Moses. Many Indian tribes have traditions that coincide with these stories. “In 1980, an entire Nivaclé native tribe of 200 people converted to the gospel when missionaries told them the story of the Savior visiting the Americas. The leader of the tribe recognized the story as one passed down from their ancestors and knew he was hearing restored truths.” (http://ldsliving.com/story/78258-tribe-knew-book-of-mormon-stories-before-missionaries-arrived-4-more-facts-about-the-church-in-paraguay) Most Mormon scholars feel the Book of Mormon peoples lived in Meso-America and may have reached northward, but that they never were a large group of people.