Complex sentence: Ross returned to the Willamette Valley in the winter of 1851 and purchased a herd of cattle, driving the cattle to the Rogue River Valley in January 1852, and opened a butcher's shop at Jacksonville, Oregon.
Split into simpler sentences: Ross returned to the Willamette Valley in the winter of 1851 and purchased a band of cattle. He drove the cattle to the Rogue River Valley in January, 1852, and opened a butcher's shop at Jacksonville, Oregon.