Complex sentence: Salt was vital to the early American frontier economy, both as a nutrient and as a means to preserve food, and Crenshaw became remarkably wealthy; at one point Crenshaw's taxes amounted to one-seventh of the revenue of the entire state.
Split into simpler sentences: Salt was vital to the early American frontier economy, both as a nutrient and as a means to preserve food. At one point, Crenshaw's taxes amounted to one-seventh of the revenue of the entire state.