Complex sentence: Shortly before settlers migrated to Brush Hill in the 1650s, a significant forest fir struck the area causing trees to die and leaves to fall, so when the settlers arrived, the hill was covered in brush, hence the name.
Split into simpler sentences: Shortly before settlers migrated to Brush Hill in the 1650s, a significant forest fire struck the area causing trees to die and leaves to fall. When the settlers arrived, the hill was covered in brush, hence the name.