Complex sentence: The typical shape of a rural district was a doughnut shaped ring around a town (which would be either an urban district or a municipal borough) and would often be fragmentary, consisting of a number of detached parts.
Split into simpler sentences: The typical shape of a rural district was a doughnut shaped ring around a town (which would be either an urban district or a municipal borough). Many rural districts were fragmentary, consisting of a number of detached parts.