April 19, 1862: Sonoma County
[We] spent two days [in Petaluma], then footed it across the ridges to Sonoma, then across to Napa—a most interesting but laborious trip.
A valley extends north from Petaluma to the Russian River—a mere low range of hills, scarcely perceptible, separating the Petaluma and the Santa Rosa valleys. They are of exceeding beauty at this time of the year, and both Petaluma and Santa Rosa are thriving villages surrounded by rich farming lands. From the high hills between Petaluma and Sonoma villages, a most beautiful view can be had of all these valleys, the bay, Mount Diablo, and the region south. We enjoyed these views much.Sonoma Valley, north of San Pablo Bay, is surrounded by high hills on three sides, and is a plain running up a number of miles, as if San Pablo Bay once occupied the ground, as it probably did in earlier times. Sheltered from the winds by high ridges on the west and north, the climate is milder than most other places on the bay, and is now obtaining some considerable renown for its vineyards and its wines.
From Sonoma we kept on east toward Napa, but did not go quite to the latter place, but returned to Sonoma, crossed the hills by stage to Petaluma Creek and returned by steamer to San Francisco. All the places I have mentioned are on your map, north of the bay.Specimens collected, April 15-19: Acer macrophyllum; Trifolium depauperatum var. amplectens; Trifolium depauperatum var. depauperatum; Vicia sativa; Lathyrus vestitus var. vestitus; Thysanocarpus radians
Gilia tricolor subsp. diffusa; Delphinium nudicaule; Linanthus dichotomus; Ranunculus aquatilis var. capillaceus; Limnanthes douglasii subsp. douglasii; Phlox gracilis; Mimulus guttatus; Astragalus breweri; Minuartia californica; Lewisia rediviva; Viola lobata subsp. lobata;
Trifolium willdenovii; Lupinus bicolor; Linanthus androsaceus; Linanthus acicularis; Ceanothus foliosus.