Sonoma County lies between Napa County and the Pacific coast and is bordered on the north by Mendocino and Lake and the south by Marin, Solano, and Contra Costa. AVAs include Alexander Valley, Dry Creek Valley, Rockpile, Bennett Valley, Knights Valley, Chalk Hill, Russian River Valley, Sonoma Valley, Moon Mountain District Sonoma County, Green Valley of Russian River Valley, Sonoma Mountain, Sonoma Coast, Northern Sonoma, Pine Mountain-Cloverdale Peak, Fort Ross-Seaview, Fountaingrove District, Petaluma Gap, and a majority of the Carneros AVA, which extends from Napa into the extreme south of the county. These AVAs cover a much larger area than the AVAs of Napa, and there is a wide variation in climate and soil throughout the county. Fertile alluvial soils, such as “Goldridge” sandy loam, characterize the valley. Green Valley is not a sub AVA of Russian River Valley but instead its own AVA, distinct for its cool temperatures, Goldridge soil, and morning fog layer. Since Green Valley is a nested AVA within Russian River Valley, producers may label their wines Green Valley or Russian River Valley, and often do this when a warmer vintage is encountered.