Complex sentence: Ch.7 the author explains the various ways the sea has been important to Selsey In the eighteenth century Selsey Bill was very much more isolated than it is today, and the sand spit extended farther out to sea.
Split into simpler sentences: Ch.7 the author explains the various ways the sea has been important to Selsey. Including wrecks, wrecking and smuggling In the eighteenth century Selsey Bill was very much more isolated than it is today, and the sand spit extended farther out to sea.