Complex sentence: Oak Lane reflected a prosperous, middle-class reputation and the growing American identity of the city's population in the early 20th century rather than the old European ethnic divisions which marked the neighborhoods that were developed in the 19th century.
Split into simpler sentences: Oak Lane reflected a prosperous, middle-class reputation. It also reflected the growing American identity of the city's population in the early 20th century instead of the old European ethnic divisions that marked the neighborhoods that were developed in the 19th century.