Complex sentence: These boundaries established a unique survey system that contorted east-to-west survey boundaries once Florida became a state and a state survey system was adopted, at which time previously existing survey systems were "grandfathered" in.
Split into simpler sentences: These boundaries established a unique survey system that contorted east-to-west survey boundaries once Florida became a state and a state survey system was adopted. Essentially, previously existing survey systems were "grandfathered" in.