Toward the southern end of Sonoma County, the Sonoma Valley runs parallel to the Napa Valley, one mountain range over to the west. The long valley is cooler in the south, closer to the ocean, where Chardonnay does very well. It was here, in the 1950s, where winemakers began developing the oaked style that would come to define California Chardonnay for years. Cabernet and Merlot predominate on the Sonoma Valley floor and on Sonoma Mountain, which forms the western side of the valley. Zinfandel also thrives with many old vines cultivated in the rolling hills of Sonoma Valley.