Complex sentence: The community thrived from the 1830s until the Civil War, and again from 1870 until 1920, by which time the boll weevil had pulled the economic rug from under Woodville, by decimating the cotton crop.
Split into simpler sentences: The community thrived from the 1830s until the Civil War. It began to recover from 1870 until 1920, by which time the boll weevil had decimated the cotton crop.