In this important and interesting book [The Book of Mormon] the history of ancient America is unfolded, from its first settlement by a colony that came from the Tower of Babel, at the confusion of languages to the beginning of the fifth century of the Christian Era. We are informed by these records that America in ancient times has been inhabited by two distinct races of people. The first were called Jaredites, and came directly from the Tower of Babel. The second race came directly from the city of Jerusalem, about six hundred years before Christ. They were principally Israelites, of the descendants of Joseph. The Jaredites were destroyed about the time that the Israelites came from Jerusalem, who succeeded them in the inheritance of the country. The principal nation of the second race fell in battle towards the close of the fourth century. The remnant are the Indians that now inhabit this country.
I guess that Joseph Smith is likewise confused on this point. Too bad Charity and other Mopologists weren't around back then to correct his obvious misunderstanding of Mormon doctrine.