What soil type is found in the eastern area of the Oak Knoll District?

The eastern area of the Oak Knoll District is characterized by sedimentary and alluvial soils. These soil types are significant in viticulture as they often have a mix of mineral content and are well-drained, making them suitable for growing high-quality grape varieties. The alluvial nature indicates that these soils are formed from sediment deposited by flowing water, which contributes to the nutrient richness necessary for viticulture. This environment typically fosters a diverse range of grape varieties and supports the production of complex wines.

Other soil types listed may not be prevalent in that specific area or may not provide the same ideal conditions for grape cultivation. For instance, gravelly loam and clay could indicate different drainage and nutrient availability impacts, while sand with high volcanic deposits usually depicts a different terroir, often associated with different flavor profiles and grape varietal suitability. Reddish gritty soil might suggest mineral-rich conditions but does not specifically describe the dominant soil types found in the eastern Oak Knoll District.